lodash.js

/**
 * @license
 * Lo-Dash 3.0.0-pre (Custom Build) <http://lodash.com/>
 * Build: `lodash modern -o ./dist/lodash.js`
 * Copyright 2012-2014 The Dojo Foundation <http://dojofoundation.org/>
 * Based on Underscore.js 1.7.0 <http://underscorejs.org/LICENSE>
 * Copyright 2009-2014 Jeremy Ashkenas, DocumentCloud and Investigative Reporters & Editors
 * Available under MIT license <http://lodash.com/license>
 */
;(function() {

  /** Used as a safe reference for `undefined` in pre ES5 environments */
  var undefined;

  /** Used as the semantic version number */
  var VERSION = '3.0.0-pre';

  /** Used to compose bitmasks for wrapper metadata */
  var BIND_FLAG = 1,
      BIND_KEY_FLAG = 2,
      CURRY_FLAG = 4,
      CURRY_RIGHT_FLAG = 8,
      CURRY_BOUND_FLAG = 16,
      PARTIAL_FLAG = 32,
      PARTIAL_RIGHT_FLAG = 64;

  /** Used as default options for `_.trunc` */
  var DEFAULT_TRUNC_LENGTH = 30,
      DEFAULT_TRUNC_OMISSION = '...';

  /** Used to detect when a function becomes hot */
  var HOT_COUNT = 150,
      HOT_SPAN = 16;

  /** Used as the TypeError message for "Functions" methods */
  var FUNC_ERROR_TEXT = 'Expected a function';

  /** Used as references for the max length and index of an array */
  var MAX_ARRAY_LENGTH = Math.pow(2, 32) - 1,
      MAX_ARRAY_INDEX =  MAX_ARRAY_LENGTH - 1;

  /**
   * Used as the maximum length of an array-like value.
   * See the [ES6 spec](http://people.mozilla.org/~jorendorff/es6-draft.html#sec-tolength)
   * for more details.
   */
  var MAX_SAFE_INTEGER = Math.pow(2, 53) - 1;

  /** Used as the internal argument placeholder */
  var PLACEHOLDER = '__lodash_placeholder__';

  /** Used to generate unique IDs */
  var idCounter = 0;

  /** Used to match empty string literals in compiled template source */
  var reEmptyStringLeading = /\b__p \+= '';/g,
      reEmptyStringMiddle = /\b(__p \+=) '' \+/g,
      reEmptyStringTrailing = /(__e\(.*?\)|\b__t\)) \+\n'';/g;

  /** Used to match HTML entities and HTML characters */
  var reEscapedHtml = /&(?:amp|lt|gt|quot|#39|#96);/g,
      reUnescapedHtml = /[&<>"'`]/g;

  /** Used to match template delimiters */
  var reEscape = /<%-([\s\S]+?)%>/g,
      reEvaluate = /<%([\s\S]+?)%>/g,
      reInterpolate = /<%=([\s\S]+?)%>/g;

  /**
   * Used to match ES6 template delimiters.
   * See the [ES6 spec](http://people.mozilla.org/~jorendorff/es6-draft.html#sec-template-literal-lexical-components)
   * for more details.
   */
  var reEsTemplate = /\$\{([^\\}]*(?:\\.[^\\}]*)*)\}/g;

  /** Used to match `RegExp` flags from their coerced string values */
  var reFlags = /\w*$/;

  /** Used to detect named functions */
  var reFuncName = /^\s*function[ \n\r\t]+\w/;

  /** Used to detect hexadecimal string values */
  var reHexPrefix = /^0[xX]/;

  /** Used to detect host constructors (Safari > 5) */
  var reHostCtor = /^\[object .+?Constructor\]$/;

  /** Used to match latin-1 supplement letters (excluding mathematical operators) */
  var reLatin1 = /[\xC0-\xD6\xD8-\xDE\xDF-\xF6\xF8-\xFF]/g;

  /** Used to ensure capturing order of template delimiters */
  var reNoMatch = /($^)/;

  /**
   * Used to match `RegExp` special characters.
   * See this [article on `RegExp` characters](http://www.regular-expressions.info/characters.html#special)
   * for more details.
   */
  var reRegExpChars = /[.*+?^${}()|[\]\/\\]/g;

  /** Used to detect functions containing a `this` reference */
  var reThis = /\bthis\b/;

  /** Used to match unescaped characters in compiled string literals */
  var reUnescapedString = /['\n\r\u2028\u2029\\]/g;

  /** Used to match words to create compound words */
  var reWords = (function() {
    var upper = '[A-Z\\xC0-\\xD6\\xD8-\\xDE]',
        lower = '[a-z\\xDF-\\xF6\\xF8-\\xFF]+';

    return RegExp(upper + '{2,}(?=' + upper + lower + ')|' + upper + '?' + lower + '|' + upper + '+|[0-9]+', 'g');
  }());

  /** Used to detect and test whitespace */
  var whitespace = (
    // whitespace
    ' \t\x0B\f\xA0\ufeff' +

    // line terminators
    '\n\r\u2028\u2029' +

    // unicode category "Zs" space separators
    '\u1680\u180E\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u202f\u205f\u3000'
  );

  /** Used to assign default `context` object properties */
  var contextProps = [
    'Array', 'ArrayBuffer', 'Date', 'Error', 'Float32Array', 'Float64Array',
    'Function', 'Int8Array', 'Int16Array', 'Int32Array', 'Math', 'Number',
    'Object', 'RegExp', 'Set', 'String', '_', 'clearTimeout', 'document',
    'isFinite', 'parseInt', 'setTimeout', 'TypeError', 'Uint8Array',
    'Uint8ClampedArray', 'Uint16Array', 'Uint32Array', 'WeakMap',
    'window', 'WinRTError'
  ];

  /** Used to make template sourceURLs easier to identify */
  var templateCounter = -1;

  /** `Object#toString` result references */
  var argsClass = '[object Arguments]',
      arrayClass = '[object Array]',
      boolClass = '[object Boolean]',
      dateClass = '[object Date]',
      errorClass = '[object Error]',
      funcClass = '[object Function]',
      mapClass = '[object Map]',
      numberClass = '[object Number]',
      objectClass = '[object Object]',
      regexpClass = '[object RegExp]',
      setClass = '[object Set]',
      stringClass = '[object String]',
      weakMapClass = '[object WeakMap]';

  var arrayBufferClass = '[object ArrayBuffer]',
      float32Class = '[object Float32Array]',
      float64Class = '[object Float64Array]',
      int8Class = '[object Int8Array]',
      int16Class = '[object Int16Array]',
      int32Class = '[object Int32Array]',
      uint8Class = '[object Uint8Array]',
      uint8ClampedClass = '[object Uint8ClampedArray]',
      uint16Class = '[object Uint16Array]',
      uint32Class = '[object Uint32Array]';

  /** Used to identify object classifications that are treated like arrays */
  var arrayLikeClasses = {};
  arrayLikeClasses[argsClass] =
  arrayLikeClasses[arrayClass] = arrayLikeClasses[float32Class] =
  arrayLikeClasses[float64Class] = arrayLikeClasses[int8Class] =
  arrayLikeClasses[int16Class] = arrayLikeClasses[int32Class] =
  arrayLikeClasses[uint8Class] = arrayLikeClasses[uint8ClampedClass] =
  arrayLikeClasses[uint16Class] = arrayLikeClasses[uint32Class] = true;
  arrayLikeClasses[arrayBufferClass] = arrayLikeClasses[boolClass] =
  arrayLikeClasses[dateClass] = arrayLikeClasses[errorClass] =
  arrayLikeClasses[funcClass] = arrayLikeClasses[mapClass] =
  arrayLikeClasses[numberClass] = arrayLikeClasses[objectClass] =
  arrayLikeClasses[regexpClass] = arrayLikeClasses[setClass] =
  arrayLikeClasses[stringClass] = arrayLikeClasses[weakMapClass] = false;

  /** Used to identify object classifications that `_.clone` supports */
  var cloneableClasses = {};
  cloneableClasses[argsClass] = cloneableClasses[arrayClass] =
  cloneableClasses[arrayBufferClass] = cloneableClasses[boolClass] =
  cloneableClasses[dateClass] = cloneableClasses[float32Class] =
  cloneableClasses[float64Class] = cloneableClasses[int8Class] =
  cloneableClasses[int16Class] = cloneableClasses[int32Class] =
  cloneableClasses[numberClass] = cloneableClasses[objectClass] =
  cloneableClasses[regexpClass] = cloneableClasses[stringClass] =
  cloneableClasses[uint8Class] = cloneableClasses[uint8ClampedClass] =
  cloneableClasses[uint16Class] = cloneableClasses[uint32Class] = true;
  cloneableClasses[errorClass] =
  cloneableClasses[funcClass] = cloneableClasses[mapClass] =
  cloneableClasses[setClass] = cloneableClasses[weakMapClass] = false;

  /** Used as an internal `_.debounce` options object by `_.throttle` */
  var debounceOptions = {
    'leading': false,
    'maxWait': 0,
    'trailing': false
  };

  /**
   * Used to map characters to HTML entities.
   *
   * **Note:** Though the ">" character is escaped for symmetry, characters like
   * ">" and "/" don't require escaping in HTML and have no special meaning
   * unless they're part of a tag or unquoted attribute value.
   * See [Mathias Bynens's article](http://mathiasbynens.be/notes/ambiguous-ampersands)
   * (under "semi-related fun fact") for more details.
   *
   * Backticks are escaped because in Internet Explorer < 9, they can break out
   * of attribute values or HTML comments. See [#102](http://html5sec.org/#102),
   * [#108](http://html5sec.org/#108), and [#133](http://html5sec.org/#133) of
   * the [HTML5 Security Cheatsheet](http://html5sec.org/) for more details.
   */
  var htmlEscapes = {
    '&': '&amp;',
    '<': '&lt;',
    '>': '&gt;',
    '"': '&quot;',
    "'": '&#39;',
    '`': '&#96;'
  };

  /** Used to map HTML entities to characters */
  var htmlUnescapes = {
    '&amp;': '&',
    '&lt;': '<',
    '&gt;': '>',
    '&quot;': '"',
    '&#39;': "'",
    '&#96;': '`'
  };

  /** Used to map latin-1 supplementary letters to basic latin letters */
  var deburredLetters = {
    '\xC0': 'A',  '\xC1': 'A', '\xC2': 'A', '\xC3': 'A', '\xC4': 'A', '\xC5': 'A',
    '\xE0': 'a',  '\xE1': 'a', '\xE2': 'a', '\xE3': 'a', '\xE4': 'a', '\xE5': 'a',
    '\xC7': 'C',  '\xE7': 'c',
    '\xD0': 'D',  '\xF0': 'd',
    '\xC8': 'E',  '\xC9': 'E', '\xCA': 'E', '\xCB': 'E',
    '\xE8': 'e',  '\xE9': 'e', '\xEA': 'e', '\xEB': 'e',
    '\xCC': 'I',  '\xCD': 'I', '\xCE': 'I', '\xCF': 'I',
    '\xEC': 'i',  '\xED': 'i', '\xEE': 'i', '\xEF': 'i',
    '\xD1': 'N',  '\xF1': 'n',
    '\xD2': 'O',  '\xD3': 'O', '\xD4': 'O', '\xD5': 'O', '\xD6': 'O', '\xD8': 'O',
    '\xF2': 'o',  '\xF3': 'o', '\xF4': 'o', '\xF5': 'o', '\xF6': 'o', '\xF8': 'o',
    '\xD9': 'U',  '\xDA': 'U', '\xDB': 'U', '\xDC': 'U',
    '\xF9': 'u',  '\xFA': 'u', '\xFB': 'u', '\xFC': 'u',
    '\xDD': 'Y',  '\xFD': 'y', '\xFF': 'y',
    '\xC6': 'Ae', '\xE6': 'ae',
    '\xDE': 'Th', '\xFE': 'th',
    '\xDF': 'ss'
  };

  /** Used to determine if values are of the language type `Object` */
  var objectTypes = {
    'function': true,
    'object': true
  };

  /** Used to escape characters for inclusion in compiled string literals */
  var stringEscapes = {
    '\\': '\\',
    "'": "'",
    '\n': 'n',
    '\r': 'r',
    '\u2028': 'u2028',
    '\u2029': 'u2029'
  };

  /** Used as a reference to the global object */
  var root = (objectTypes[typeof window] && window) || this;

  /** Detect free variable `exports` */
  var freeExports = objectTypes[typeof exports] && exports && !exports.nodeType && exports;

  /** Detect free variable `module` */
  var freeModule = objectTypes[typeof module] && module && !module.nodeType && module;

  /** Detect free variable `global` from Node.js or Browserified code and use it as `root` */
  var freeGlobal = freeExports && freeModule && typeof global == 'object' && global;
  if (freeGlobal && (freeGlobal.global === freeGlobal || freeGlobal.window === freeGlobal || freeGlobal.self === freeGlobal)) {
    root = freeGlobal;
  }

  /** Detect the popular CommonJS extension `module.exports` */
  var moduleExports = freeModule && freeModule.exports === freeExports && freeExports;

  /*--------------------------------------------------------------------------*/

  /**
   * A specialized version of `_.forEach` for arrays without support for
   * callback shorthands or `this` binding.
   *
   * @private
   * @param {Array} array The array to iterate over.
   * @param {Function} iteratee The function invoked per iteration.
   * @returns {Array} Returns `array`.
   */
  function arrayEach(array, iteratee) {
    var index = -1,
        length = array.length;

    while (++index < length) {
      if (iteratee(array[index], index, array) === false) {
        break;
      }
    }
    return array;
  }

  /**
   * A specialized version of `_.forEachRight` for arrays without support for
   * callback shorthands or `this` binding.
   *
   * @private
   * @param {Array} array The array to iterate over.
   * @param {Function} iteratee The function invoked per iteration.
   * @returns {Array} Returns `array`.
   */
  function arrayEachRight(array, iteratee) {
    var length = array.length;

    while (length--) {
      if (iteratee(array[length], length, array) === false) {
        break;
      }
    }
    return array;
  }

  /**
   * A specialized version of `_.every` for arrays without support for callback
   * shorthands or `this` binding.
   *
   * @private
   * @param {Array} array The array to iterate over.
   * @param {Function} predicate The function invoked per iteration.
   * @returns {Array} Returns `true` if all elements pass the predicate check,
   *  else `false`
   */
  function arrayEvery(array, predicate) {
    var index = -1,
        length = array.length;

    while (++index < length) {
      if (!predicate(array[index], index, array)) {
        return false;
      }
    }
    return true;
  }

  /**
   * A specialized version of `_.map` for arrays without support for callback
   * shorthands or `this` binding.
   *
   * @private
   * @param {Array} array The array to iterate over.
   * @param {Function} iteratee The function invoked per iteration.
   * @returns {Array} Returns the new mapped array.
   */
  function arrayMap(array, iteratee) {
    var index = -1,
        length = array.length,
        result = Array(length);

    while (++index < length) {
      result[index] = iteratee(array[index], index, array);
    }
    return result;
  }

  /**
   * A specialized version of `_.filter` for arrays without support for callback
   * shorthands or `this` binding.
   *
   * @private
   * @param {Array} array The array to iterate over.
   * @param {Function} predicate The function invoked per iteration.
   * @returns {Array} Returns the new filtered array.
   */
  function arrayFilter(array, predicate) {
    var index = -1,
        length = array.length,
        resIndex = -1,
        result = [];

    while (++index < length) {
      var value = array[index];
      if (predicate(value, index, array)) {
        result[++resIndex] = value;
      }
    }
    return result;
  }

  /**
   * A specialized version of `_.reduce` for arrays without support for callback
   * shorthands or `this` binding.
   *
   * @private
   * @param {Array} array The array to iterate over.
   * @param {Function} iteratee The function invoked per iteration.
   * @param {*} [accumulator] The initial value.
   * @param {boolean} [initFromArray=false] Specify using the first element of
   *  `array` as the initial value.
   * @returns {*} Returns the accumulated value.
   */
  function arrayReduce(array, iteratee, accumulator, initFromArray) {
    var index = -1,
        length = array.length;

    if (initFromArray && length) {
      accumulator = array[++index];
    }
    while (++index < length) {
      accumulator = iteratee(accumulator, array[index], index, array);
    }
    return accumulator;
  }

  /**
   * A specialized version of `_.reduceRight` for arrays without support for
   * callback shorthands or `this` binding.
   *
   * @private
   * @param {Array} array The array to iterate over.
   * @param {Function} iteratee The function invoked per iteration.
   * @param {*} [accumulator] The initial value.
   * @param {boolean} [initFromArray=false] Specify using the last element of
   *  `array` as the initial value.
   * @returns {*} Returns the accumulated value.
   */
  function arrayReduceRight(array, iteratee, accumulator, initFromArray) {
    var length = array.length;

    if (initFromArray && length) {
      accumulator = array[--length];
    }
    while (length--) {
      accumulator = iteratee(accumulator, array[length], length, array);
    }
    return accumulator;
  }

  /**
   * A specialized version of `_.some` for arrays without support for callback
   * shorthands or `this` binding.
   *
   * @private
   * @param {Array} array The array to iterate over.
   * @param {Function} predicate The function invoked per iteration.
   * @returns {boolean} Returns `true` if any element passes the predicate check,
   *  else `false`.
   */
  function arraySome(array, predicate) {
    var index = -1,
        length = array.length;

    while (++index < length) {
      if (predicate(array[index], index, array)) {
        return true;
      }
    }
    return false;
  }

  /**
   * The base implementation of `_.at` without support for strings and individual
   * key arguments.
   *
   * @private
   * @param {Array|Object} collection The collection to iterate over.
   * @param {number[]|string[]} [props] The property names or indexes of elements to pick.
   * @returns {Array} Returns the new array of picked elements.
   */
  function baseAt(collection, props) {
    var index = -1,
        length = props.length,
        result = Array(length);

    while(++index < length) {
      result[index] = collection[props[index]];
    }
    return result;
  }

  /**
   * The base implementation of `compareAscending` which compares values and
   * sorts them in ascending order without guaranteeing a stable sort.
   *
   * @private
   * @param {*} value The value to compare to `other`.
   * @param {*} other The value to compare to `value`.
   * @returns {number} Returns the sort order indicator for `value`.
   */
  function baseCompareAscending(value, other) {
    if (value !== other) {
      var valIsReflexive = value === value,
          othIsReflexive = other === other;

      if (value > other || !valIsReflexive || (typeof value == 'undefined' && othIsReflexive)) {
        return 1;
      }
      if (value < other || !othIsReflexive || (typeof other == 'undefined' && valIsReflexive)) {
        return -1;
      }
    }
    return 0;
  }

  /**
   * The base implementation of `_.indexOf` without support for `fromIndex`
   * bounds checks and binary searches.
   *
   * @private
   * @param {Array} array The array to search.
   * @param {*} value The value to search for.
   * @param {number} [fromIndex=0] The index to search from.
   * @returns {number} Returns the index of the matched value, else `-1`.
   */
  function baseIndexOf(array, value, fromIndex) {
    if (value !== value) {
      return indexOfNaN(array, fromIndex);
    }
    var index = (fromIndex || 0) - 1,
        length = array.length;

    while (++index < length) {
      if (array[index] === value) {
        return index;
      }
    }
    return -1;
  }

  /**
   * The base implementation of `_.slice` without support for `start` and `end`
   * arguments.
   *
   * @private
   * @param {Array} array The array to slice.
   * @returns {Array} Returns the slice of `array`.
   */
  function baseSlice(array) {
    var index = -1,
        length = array ? array.length : 0,
        result = Array(length);

    while (++index < length) {
      result[index] = array[index];
    }
    return result;
  }

  /**
   * An implementation of `_.contains` for cache objects that mimics the return
   * signature of `_.indexOf` by returning `0` if the value is found, else `-1`.
   *
   * @private
   * @param {Object} cache The cache object to inspect.
   * @param {*} value The value to search for.
   * @returns {number} Returns `0` if `value` is found, else `-1`.
   */
  function cacheIndexOf(cache, value) {
    return cache.has(value) ? 0 : -1;
  }

  /**
   * Used by `_.max` and `_.min` as the default callback when a given collection
   * is a string value.
   *
   * @private
   * @param {string} string The string to inspect.
   * @returns {number} Returns the code unit of the first character of the string.
   */
  function charAtCallback(string) {
    return string.charCodeAt(0);
  }

  /**
   * Used by `_.trim` and `_.trimLeft` to get the index of the first character
   * of `string` that is not found in `chars`.
   *
   * @private
   * @param {string} string The string to inspect.
   * @param {string} chars The characters to find.
   * @returns {number} Returns the index of the first character not found in `chars`.
   */
  function charsLeftIndex(string, chars) {
    var index = -1,
        length = string.length;

    while (++index < length && chars.indexOf(string.charAt(index)) > -1) {}
    return index;
  }

  /**
   * Used by `_.trim` and `_.trimRight` to get the index of the last character
   * of `string` that is not found in `chars`.
   *
   * @private
   * @param {string} string The string to inspect.
   * @param {string} chars The characters to find.
   * @returns {number} Returns the index of the last character not found in `chars`.
   */
  function charsRightIndex(string, chars) {
    var index = string.length;

    while (index-- && chars.indexOf(string.charAt(index)) > -1) {}
    return index;
  }

  /**
   * Used by `_.sortBy` to compare transformed elements of `collection` and stable
   * sort them in ascending order.
   *
   * @private
   * @param {Object} object The object to compare to `other`.
   * @param {Object} other The object to compare to `object`.
   * @returns {number} Returns the sort order indicator for `object`.
   */
  function compareAscending(object, other) {
    return baseCompareAscending(object.criteria, other.criteria) || (object.index - other.index);
  }

  /**
   * Used by `_.sortBy` to compare multiple properties of each element in a
   * collection and stable sort them in ascending order.
   *
   * @private
   * @param {Object} object The object to compare to `other`.
   * @param {Object} other The object to compare to `object`.
   * @returns {number} Returns the sort order indicator for `object`.
   */
  function compareMultipleAscending(object, other) {
    var index = -1,
        objCriteria = object.criteria,
        othCriteria = other.criteria,
        length = objCriteria.length;

    while (++index < length) {
      var result = baseCompareAscending(objCriteria[index], othCriteria[index]);
      if (result) {
        return result;
      }
    }
    // Fixes an `Array#sort` bug in the JS engine embedded in Adobe applications
    // that causes it, under certain circumstances, to provide the same value
    // for `object` and `other`. See https://github.com/jashkenas/underscore/pull/1247
    //
    // This also ensures a stable sort in V8 and other engines.
    // See https://code.google.com/p/v8/issues/detail?id=90
    return object.index - other.index;
  }

  /**
   * Used by `deburr` to convert latin-1 to basic latin letters.
   *
   * @private
   * @param {string} letter The matched letter to deburr.
   * @returns {string} Returns the deburred letter.
   */
  function deburrLetter(letter) {
    return deburredLetters[letter];
  }

  /**
   * Used by `_.escape` to convert characters to HTML entities.
   *
   * @private
   * @param {string} chr The matched character to escape.
   * @returns {string} Returns the escaped character.
   */
  function escapeHtmlChar(chr) {
    return htmlEscapes[chr];
  }

  /**
   * Used by `_.template` to escape characters for inclusion in compiled
   * string literals.
   *
   * @private
   * @param {string} chr The matched character to escape.
   * @returns {string} Returns the escaped character.
   */
  function escapeStringChar(chr) {
    return '\\' + stringEscapes[chr];
  }

  /**
   * Gets the index at which the first occurrence of `NaN` is found in `array`.
   * If `fromRight` is provided elements of `array` are iterated from right to left.
   *
   * @private
   * @param {Array} array The array to search.
   * @param {number} [fromIndex] The index to search from.
   * @param {boolean} [fromRight=false] Specify iterating from right to left.
   * @returns {number} Returns the index of the matched `NaN`, else `-1`.
   */
  function indexOfNaN(array, fromIndex, fromRight) {
    var length = array.length,
        index = fromRight ? (fromIndex || length) : ((fromIndex || 0) - 1);

    while ((fromRight ? index-- : ++index < length)) {
      var other = array[index];
      if (other !== other) {
        return index;
      }
    }
    return -1;
  }

  /**
   * Checks if the provided arguments are from an iteratee call.
   *
   * @private
   * @param {*} value The potential iteratee value argument.
   * @param {*} index The potential iteratee index or key argument.
   * @param {*} object The potential iteratee object argument.
   * @returns {boolean} Returns `true` if the arguments are from an iteratee call, else `false`.
   */
  function isIterateeCall(value, index, object) {
    var indexType = typeof index,
        objectType = typeof object;

    return (object && (indexType == 'number' || indexType == 'string') &&
      (objectType == 'function' || objectType == 'object') && object[index] === value) || false;
  }

  /**
   * Used by `_.trimmedLeftIndex` and `_.trimmedRightIndex` to determine if a
   * character code is whitespace.
   *
   * @private
   * @param {number} charCode The character code to inspect.
   * @returns {boolean} Returns `true` if `charCode` is whitespace, else `false`.
   */
  function isWhitespace(charCode) {
    return ((charCode <= 160 && (charCode >= 9 && charCode <= 13) || charCode == 32 || charCode == 160) || charCode == 5760 || charCode == 6158 ||
      (charCode >= 8192 && (charCode <= 8202 || charCode == 8232 || charCode == 8233 || charCode == 8239 || charCode == 8287 || charCode == 12288 || charCode == 65279)));
  }

  /**
   * Replaces all `placeholder` elements in `array` with an internal placeholder
   * and returns an array of their indexes.
   *
   * @private
   * @param {Array} array The array to modify.
   * @param {*} placeholder The placeholder to replace.
   * @returns {Array} Returns the new array of placeholder indexes.
   */
  function replaceHolders(array, placeholder) {
    var index = -1,
        length = array.length,
        resIndex = -1,
        result = [];

    while (++index < length) {
      if (array[index] === placeholder) {
        array[index] = PLACEHOLDER;
        result[++resIndex] = index;
      }
    }
    return result;
  }

  /**
   * An implementation of `_.uniq` optimized for sorted arrays without support
   * for callback shorthands and `this` binding.
   *
   * @private
   * @param {Array} array The array to inspect.
   * @param {Function} [iteratee] The function invoked per iteration.
   * @returns {Array} Returns the new duplicate-value-free array.
   */
  function sortedUniq(array, iteratee) {
    var seen,
        index = -1,
        length = array.length,
        resIndex = -1,
        result = [];

    while (++index < length) {
      var value = array[index],
          computed = iteratee ? iteratee(value, index, array) : value;

      if (!index || seen !== computed) {
        seen = computed;
        result[++resIndex] = value;
      }
    }
    return result;
  }

  /**
   * Used by `_.trim` and `_.trimLeft` to get the index of the first non-whitespace
   * character of `string`.
   *
   * @private
   * @param {string} string The string to inspect.
   * @returns {number} Returns the index of the first non-whitespace character.
   */
  function trimmedLeftIndex(string) {
    var index = -1,
        length = string.length;

    while (++index < length && isWhitespace(string.charCodeAt(index))) {}
    return index;
  }

  /**
   * Used by `_.trim` and `_.trimRight` to get the index of the last non-whitespace
   * character of `string`.
   *
   * @private
   * @param {string} string The string to inspect.
   * @returns {number} Returns the index of the last non-whitespace character.
   */
  function trimmedRightIndex(string) {
    var index = string.length;

    while (index-- && isWhitespace(string.charCodeAt(index))) {}
    return index;
  }

  /**
   * Used by `_.unescape` to convert HTML entities to characters.
   *
   * @private
   * @param {string} chr The matched character to unescape.
   * @returns {string} Returns the unescaped character.
   */
  function unescapeHtmlChar(chr) {
    return htmlUnescapes[chr];
  }

  /*--------------------------------------------------------------------------*/

  /**
   * Create a new pristine `lodash` function using the given `context` object.
   *
   * @static
   * @memberOf _
   * @category Utility
   * @param {Object} [context=root] The context object.
   * @returns {Function} Returns a new `lodash` function.
   * @example
   *
   * _.mixin({ 'add': function(a, b) { return a + b; } }, false);
   *
   * var lodash = _.runInContext();
   * lodash.mixin({ 'sub': function(a, b) { return a - b; } }, false);
   *
   * _.isFunction(_.add);
   * // => true
   *
   * _.isFunction(_.sub);
   * // => false
   *
   * lodash.isFunction(lodash.add);
   * // => false
   *
   * lodash.isFunction(lodash.sub);
   * // => true
   */
  function runInContext(context) {
    // Avoid issues with some ES3 environments that attempt to use values, named
    // after built-in constructors like `Object`, for the creation of literals.
    // ES5 clears this up by stating that literals must use built-in constructors.
    // See http://es5.github.io/#x11.1.5.
    context = context ? _.defaults(root.Object(), context, _.pick(root, contextProps)) : root;

    /** Native constructor references */
    var Array = context.Array,
        Date = context.Date,
        Error = context.Error,
        Function = context.Function,
        Math = context.Math,
        Number = context.Number,
        Object = context.Object,
        RegExp = context.RegExp,
        String = context.String,
        TypeError = context.TypeError;

    /** Used for native method references */
    var arrayProto = Array.prototype,
        objectProto = Object.prototype;

    /** Used to detect DOM support */
    var document = (document = context.window) && document.document;

    /** Used to resolve the decompiled source of functions */
    var fnToString = Function.prototype.toString;

    /** Used to check objects for own properties */
    var hasOwnProperty = objectProto.hasOwnProperty;

    /** Used to restore the original `_` reference in `_.noConflict` */
    var oldDash = context._;

    /** Used to resolve the internal `[[Class]]` of values */
    var toString = objectProto.toString;

    /** Used to detect if a method is native */
    var reNative = RegExp('^' +
      escapeRegExp(toString)
      .replace(/toString|(function).*?(?=\\\()| for .+?(?=\\\])/g, '$1.*?') + '$'
    );

    /** Native method references */
    var ArrayBuffer = isNative(ArrayBuffer = context.ArrayBuffer) && ArrayBuffer,
        bufferSlice = isNative(bufferSlice = ArrayBuffer && new ArrayBuffer(0).slice) && bufferSlice,
        ceil = Math.ceil,
        clearTimeout = context.clearTimeout,
        floor = Math.floor,
        getPrototypeOf = isNative(getPrototypeOf = Object.getPrototypeOf) && getPrototypeOf,
        push = arrayProto.push,
        propertyIsEnumerable = objectProto.propertyIsEnumerable,
        Set = isNative(Set = context.Set) && Set,
        setTimeout = context.setTimeout,
        splice = arrayProto.splice,
        Uint8Array = isNative(Uint8Array = context.Uint8Array) && Uint8Array,
        unshift = arrayProto.unshift,
        WeakMap = isNative(WeakMap = context.WeakMap) && WeakMap;

    /** Used to clone array buffers */
    var Float64Array = (function() {
      // Safari 5 errors when using an array buffer to initialize a typed array
      // where the array buffer's `byteLength` is not a multiple of the typed
      // array's `BYTES_PER_ELEMENT`
      try {
        var func = isNative(func = context.Float64Array) && func,
            result = new func(new ArrayBuffer(10), 0, 1) && func;
      } catch(e) {}
      return result;
    }());

    /* Native method references for those with the same name as other `lodash` methods */
    var nativeCreate = isNative(nativeCreate = Object.create) && nativeCreate,
        nativeIsArray = isNative(nativeIsArray = Array.isArray) && nativeIsArray,
        nativeIsFinite = context.isFinite,
        nativeKeys = isNative(nativeKeys = Object.keys) && nativeKeys,
        nativeMax = Math.max,
        nativeMin = Math.min,
        nativeNow = isNative(nativeNow = Date.now) && nativeNow,
        nativeNumIsFinite = isNative(nativeNumIsFinite = Number.isFinite) && nativeNumIsFinite,
        nativeParseInt = context.parseInt,
        nativeRandom = Math.random;

    /** Used as the size, in bytes, of each Float64Array element */
    var FLOAT64_BYTES_PER_ELEMENT = Float64Array ? Float64Array.BYTES_PER_ELEMENT : 0;

    /** Used to store function metadata */
    var metaMap = WeakMap && new WeakMap;

    /*------------------------------------------------------------------------*/

    /**
     * Creates a `lodash` object which wraps the given value to enable intuitive
     * method chaining.
     *
     * In addition to Lo-Dash methods, wrappers also have the following `Array` methods:
     * `concat`, `join`, `pop`, `push`, `reverse`, `shift`, `slice`, `sort`, `splice`,
     * and `unshift`
     *
     * Chaining is supported in custom builds as long as the `value` method is
     * implicitly or explicitly included in the build.
     *
     * The chainable wrapper functions are:
     * `after`, `assign`, `at`, `before`, `bind`, `bindAll`, `bindKey`, `callback`,
     * `chain`, `chunk`, `compact`, `concat`, `constant`, `countBy`, `create`,
     * `curry`, `debounce`, `defaults`, `defer`, `delay`, `difference`, `drop`,
     * `dropRight`, `dropRightWhile`, `dropWhile`, `filter`, `flatten`, `flattenDeep`,
     * `flow`, `flowRight`, `forEach`, `forEachRight`, `forIn`, `forInRight`,
     * `forOwn`, `forOwnRight`, `functions`, `groupBy`, `indexBy`, `initial`,
     * `intersection`, `invert`, `invoke`, `keys`, `keysIn`, `map`, `mapValues`,
     * `matches`, `memoize`, `merge`, `mixin`, `negate`, `noop`, `omit`, `once`,
     * `pairs`, `partial`, `partialRight`, `partition`, `pick`, `pluck`, `property`,
     * `pull`, `pullAt`, `push`, `range`, `reject`, `remove`, `rest`, `reverse`,
     * `shuffle`, `slice`, `sort`, `sortBy`, `splice`, `take`, `takeRight`,
     * `takeRightWhile`, `takeWhile`, `tap`, `throttle`, `thru`, `times`,
     * `toArray`, `transform`, `union`, `uniq`, `unshift`, `unzip`, `values`,
     * `valuesIn`, `where`, `without`, `wrap`, `xor`, `zip`, and `zipObject`
     *
     * The non-chainable wrapper functions are:
     * `attempt`, `camelCase`, `capitalize`, `clone`, `cloneDeep`, `contains`,
     * `deburr`, endsWith`, `escape`, `escapeRegExp`, `every`, `find`, `findIndex`,
     * `findKey`, `findLast`, `findLastIndex`, `findLastKey`, `findWhere`, `first`,
     * `has`, `identity`, `indexOf`, `isArguments`, `isArray`, `isBoolean`, isDate`,
     * `isElement`, `isEmpty`, `isEqual`, `isError`, `isFinite`, `isFunction`,
     * `isNative`, `isNaN`, `isNull`, `isNumber`, `isObject`, `isPlainObject`,
     * `isRegExp`, `isString`, `isUndefined`, `join`, `kebabCase`, `last`,
     * `lastIndexOf`, `max`, `min`, `noConflict`, `now`, `pad`, `padLeft`,
     * `padRight`, `parseInt`, `pop`, `random`, `reduce`, `reduceRight`, `repeat`,
     * `result`, `runInContext`, `shift`, `size`, `snakeCase`, `some`, `sortedIndex`,
     * `sortedLastIndex`, `startsWith`, `template`, `trim`, `trimLeft`, `trimRight`,
     * `trunc`, `unescape`, `uniqueId`, `value`, and `words`
     *
     * The wrapper function `sample` will return a wrapped value when `n` is
     * provided, otherwise it will return an unwrapped value.
     *
     * Explicit chaining can be enabled by using the `_.chain` method.
     *
     * @name _
     * @constructor
     * @category Chain
     * @param {*} value The value to wrap in a `lodash` instance.
     * @returns {Object} Returns a `lodash` instance.
     * @example
     *
     * var wrapped = _([1, 2, 3]);
     *
     * // returns an unwrapped value
     * wrapped.reduce(function(sum, n) { return sum + n; });
     * // => 6
     *
     * // returns a wrapped value
     * var squares = wrapped.map(function(n) { return n * n; });
     *
     * _.isArray(squares);
     * // => false
     *
     * _.isArray(squares.value());
     * // => true
     */
    function lodash(value) {
      if (value && typeof value == 'object') {
        if (value instanceof lodashWrapper) {
          return value;
        }
        if (!isArray(value) && hasOwnProperty.call(value, '__wrapped__')) {
          return new lodashWrapper(value.__wrapped__, value.__chain__, baseSlice(value.__queue__));
        }
      }
      return new lodashWrapper(value);
    }

    /**
     * A fast path for creating `lodash` wrapper objects.
     *
     * @private
     * @param {*} value The value to wrap in a `lodash` instance.
     * @param {boolean} [chainAll=false] Enable chaining for all methods.
     * @param {Array} [queue=[]] Actions to peform to resolve the unwrapped value.
     * @returns {Object} Returns a `lodash` instance.
     */
    function lodashWrapper(value, chainAll, queue) {
      this.__chain__ = !!chainAll;
      this.__queue__ = queue || [];
      this.__wrapped__ = value;
    }

    /**
     * An object environment feature flags.
     *
     * @static
     * @memberOf _
     * @type Object
     */
    var support = lodash.support = {};

    (function(x) {

      /**
       * Detect if functions can be decompiled by `Function#toString`
       * (all but Firefox OS certified apps, older Opera mobile browsers, and
       * the PlayStation 3; forced `false` for Windows 8 apps).
       *
       * @memberOf _.support
       * @type boolean
       */
      support.funcDecomp = !isNative(context.WinRTError) && reThis.test(runInContext);

      /**
       * Detect if `Function#name` is supported (all but IE).
       *
       * @memberOf _.support
       * @type boolean
       */
      support.funcNames = typeof Function.name == 'string';

      /**
       * Detect if the DOM is supported.
       *
       * @memberOf _.support
       * @type boolean
       */
      try {
        support.dom = document.createDocumentFragment().nodeType === 11;
      } catch(e) {
        support.dom = false;
      }

      /**
       * Detect if `arguments` object indexes are non-enumerable.
       *
       * In Firefox < 4, IE < 9, PhantomJS, and Safari < 5.1 `arguments` object
       * indexes are non-enumerable. Chrome < 25 and Node.js < 0.11.0 treat
       * `arguments` object indexes as non-enumerable and fail `hasOwnProperty`
       * checks for indexes that exceed their function's formal parameters with
       * associated values of `0`.
       *
       * @memberOf _.support
       * @type boolean
       */
      try {
        support.nonEnumArgs = !propertyIsEnumerable.call(arguments, 1);
      } catch(e) {
        support.nonEnumArgs = true;
      }
    }(0, 0));

    /**
     * By default, the template delimiters used by Lo-Dash are similar to those
     * in embedded Ruby (ERB). Change the following template settings to use
     * alternative delimiters.
     *
     * @static
     * @memberOf _
     * @type Object
     */
    lodash.templateSettings = {

      /**
       * Used to detect `data` property values to be HTML-escaped.
       *
       * @memberOf _.templateSettings
       * @type RegExp
       */
      'escape': reEscape,

      /**
       * Used to detect code to be evaluated.
       *
       * @memberOf _.templateSettings
       * @type RegExp
       */
      'evaluate': reEvaluate,

      /**
       * Used to detect `data` property values to inject.
       *
       * @memberOf _.templateSettings
       * @type RegExp
       */
      'interpolate': reInterpolate,

      /**
       * Used to reference the data object in the template text.
       *
       * @memberOf _.templateSettings
       * @type string
       */
      'variable': '',

      /**
       * Used to import variables into the compiled template.
       *
       * @memberOf _.templateSettings
       * @type Object
       */
      'imports': {

        /**
         * A reference to the `lodash` function.
         *
         * @memberOf _.templateSettings.imports
         * @type Function
         */
        '_': lodash
      }
    };

    /*------------------------------------------------------------------------*/

    /**
     * Used by `_.defaults` to customize its `_.assign` use.
     *
     * @private
     * @param {*} objectValue The destination object property value.
     * @param {*} sourceValue The source object property value.
     * @returns {*} Returns the value to assign to the destination object.
     */
    function assignDefaults(objectValue, sourceValue) {
      return typeof objectValue == 'undefined'
        ? sourceValue
        : objectValue;
    }

    /**
     * Used by `_.template` to customize its `_.assign` use.
     *
     * **Note:** This method is like `assignDefaults` except that it ignores
     * inherited property values when checking if a property is `undefined`.
     *
     * @private
     * @param {*} objectValue The destination object property value.
     * @param {*} sourceValue The source object property value.
     * @param {string} key The key associated with the object and source values.
     * @param {Object} object The destination object.
     * @returns {*} Returns the value to assign to the destination object.
     */
    function assignOwnDefaults(objectValue, sourceValue, key, object) {
      return (typeof objectValue == 'undefined' || !hasOwnProperty.call(object, key))
        ? sourceValue
        : objectValue;
    }

    /**
     * The base implementation of `_.assign` without support for argument juggling,
     * multiple sources, and `this` binding.
     *
     * @private
     * @param {Object} object The destination object.
     * @param {Object} source The source object.
     * @param {Function} [customizer] The function to customize assigning values.
     * @returns {Object} Returns the destination object.
     */
    function baseAssign(object, source, customizer) {
      var index = -1,
          props = keys(source),
          length = props.length;

      while (++index < length) {
        var key = props[index];
        object[key] = customizer
          ? customizer(object[key], source[key], key, object, source)
          : source[key];
      }
      return object;
    }

    /**
     * The base implementation of `_.bindAll` without support for individual
     * method name arguments.
     *
     * @private
     * @param {Object} object The object to bind and assign the bound methods to.
     * @param {string[]} methodNames The object method names to bind.
     * @returns {Object} Returns `object`.
     */
    function baseBindAll(object, methodNames) {
      var index = -1,
          length = methodNames.length;

      while (++index < length) {
        var key = methodNames[index];
        object[key] = createWrapper(object[key], BIND_FLAG, null, object);
      }
      return object;
    }

    /**
     * The base implementation of `_.callback` without support for creating
     * "_.pluck" and "_.where" style callbacks.
     *
     * @private
     * @param {*} [func=identity] The value to convert to a callback.
     * @param {*} [thisArg] The `this` binding of the created callback.
     * @param {number} [argCount] The number of arguments the callback accepts.
     * @returns {Function} Returns the new function.
     */
    function baseCallback(func, thisArg, argCount) {
      var type = typeof func;

      if (type == 'function') {
        if (typeof thisArg == 'undefined') {
          return func;
        }
        var data = getData(func);
        if (typeof data == 'undefined') {
          if (support.funcNames) {
            data = !func.name;
          }
          data = data || !support.funcDecomp;
          if (!data) {
            var source = fnToString.call(func);
            if (!support.funcNames) {
              data = !reFuncName.test(source);
            }
            if (!data) {
              // checks if `func` references the `this` keyword and stores the result
              data = reThis.test(source) || isNative(func);
              baseSetData(func, data);
            }
          }
        }
        // exit early if there are no `this` references or `func` is bound
        if (data === false || (data !== true && data[1] & BIND_FLAG)) {
          return func;
        }
        switch (argCount) {
          case 1: return function(value) {
            return func.call(thisArg, value);
          };
          case 3: return function(value, index, collection) {
            return func.call(thisArg, value, index, collection);
          };
          case 4: return function(accumulator, value, index, collection) {
            return func.call(thisArg, accumulator, value, index, collection);
          };
          case 5: return function(value, other, key, object, source) {
            return func.call(thisArg, value, other, key, object, source);
          };
        }
        return function() {
          return func.apply(thisArg, arguments);
        };
      }
      if (func == null) {
        return identity;
      }
      // handle "_.pluck" and "_.where" style callback shorthands
      return type == 'object' ? matches(func) : property(func);
    }

    /**
     * The base implementation of `_.clone` without support for argument juggling
     * and `this` binding.
     *
     * @private
     * @param {*} value The value to clone.
     * @param {boolean} [isDeep=false] Specify a deep clone.
     * @param {Function} [customizer] The function to customize cloning values.
     * @param {Array} [stackA=[]] Tracks traversed source objects.
     * @param {Array} [stackB=[]] Associates clones with source counterparts.
     * @returns {*} Returns the cloned value.
     */
    function baseClone(value, isDeep, customizer, stackA, stackB) {
      var result = customizer ? customizer(value) : undefined;
      if (typeof result != 'undefined') {
        return result;
      }
      var isArr = isArray(value);
      result = value;
      if (isArr) {
        result = initArrayClone(value, isDeep);
      } else if (isObject(value)) {
        result = initObjectClone(value, isDeep);
        value = (isDeep && toString.call(result) == objectClass) ? value : result;
      }
      if (!isDeep || result === value) {
        return result;
      }
      // check for circular references and return corresponding clone
      stackA || (stackA = []);
      stackB || (stackB = []);

      var length = stackA.length;
      while (length--) {
        if (stackA[length] == value) {
          return stackB[length];
        }
      }
      // add the source value to the stack of traversed objects
      // and associate it with its clone
      stackA.push(value);
      stackB.push(result);

      // recursively populate clone (susceptible to call stack limits)
      (isArr ? arrayEach : baseForOwn)(value, function(valValue, key) {
        var valClone = customizer ? customizer(valValue, key) : undefined;
        result[key] = typeof valClone == 'undefined'
          ? baseClone(valValue, isDeep, null, stackA, stackB)
          : valClone;
      });
      return result;
    }

    /**
     * The base implementation of `_.create` without support for assigning
     * properties to the created object.
     *
     * @private
     * @param {Object} prototype The object to inherit from.
     * @returns {Object} Returns the new object.
     */
    function baseCreate(prototype) {
      return isObject(prototype) ? nativeCreate(prototype) : {};
    }
    // fallback for environments without `Object.create`
    if (!nativeCreate) {
      baseCreate = (function() {
        function Object() {}
        return function(prototype) {
          if (isObject(prototype)) {
            Object.prototype = prototype;
            var result = new Object;
            Object.prototype = null;
          }
          return result || context.Object();
        };
      }());
    }

    /**
     * The base implementation of `_.curry` and `_.curryRight` which handles
     * resolving the default arity of `func`.
     *
     * @private
     * @param {Function} func The function to curry.
     * @param {number} bitmask The bitmask of flags to compose.
     * @param {number} [arity=func.length] The arity of `func`.
     * @returns {Function} Returns the new curried function.
     */
    function baseCurry(func, bitmask, arity) {
      if (typeof arity != 'number') {
        arity = arity == null ? (func ? func.length : 0) : nativeMax(+arity || 0, 0);
      }
      return createWrapper(func, bitmask, arity);
    }

    /**
     * The base implementation of `_.difference` which accepts a single array
     * of values to exclude.
     *
     * @private
     * @param {Array} array The array to inspect.
     * @param {Array} values The values to exclude.
     * @returns {Array} Returns the new array of filtered values.
     */
    function baseDifference(array, values) {
      var length = array ? array.length : 0;
      if (!length) {
        return [];
      }
      var index = -1,
          indexOf = getIndexOf(),
          prereq = indexOf == baseIndexOf,
          isLarge = prereq && createCache && values && values.length >= 200,
          isCommon = prereq && !isLarge,
          result = [],
          valuesLength = values.length;

      if (isLarge) {
        indexOf = cacheIndexOf;
        values = createCache(values);
      }
      outer:
      while (++index < length) {
        var value = array[index];

        if (isCommon && value === value) {
          var valuesIndex = valuesLength;
          while (valuesIndex--) {
            if (values[valuesIndex] === value) {
              continue outer;
            }
          }
          result.push(value);
        }
        else if (indexOf(values, value) < 0) {
          result.push(value);
        }
      }
      return result;
    }

    /**
     * The base implementation of `_.forEach` without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Array|Object|string} Returns `collection`.
     */
    function baseEach(collection, iteratee) {
      var length = collection ? collection.length : 0;
      if (!(typeof length == 'number' && length > -1 && length <= MAX_SAFE_INTEGER)) {
        return baseForOwn(collection, iteratee);
      }
      var index = -1,
          iterable = toObject(collection);

      while (++index < length) {
        if (iteratee(iterable[index], index, iterable) === false) {
          break;
        }
      }
      return collection;
    }

    /**
     * The base implementation of `_.forEachRight` without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Array|Object|string} Returns `collection`.
     */
    function baseEachRight(collection, iteratee) {
      var length = collection ? collection.length : 0;
      if (!(typeof length == 'number' && length > -1 && length <= MAX_SAFE_INTEGER)) {
        return baseForOwnRight(collection, iteratee);
      }
      var iterable = toObject(collection);
      while (length--) {
        if (iteratee(iterable[length], length, iterable) === false) {
          break;
        }
      }
      return collection;
    }

    /**
     * The base implementation of `_.every` without support for callback
     * shorthands or `this` binding.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} predicate The function invoked per iteration.
     * @returns {Array} Returns `true` if all elements pass the predicate check,
     *  else `false`
     */
    function baseEvery(collection, predicate) {
      var result = true;

      baseEach(collection, function(value, index, collection) {
        result = !!predicate(value, index, collection);
        return result;
      });
      return result;
    }

    /**
     * The base implementation of `_.filter` without support for callback shorthands
     * or `this` binding.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} predicate The function invoked per iteration.
     * @returns {Array} Returns the new filtered array.
     */
    function baseFilter(collection, predicate) {
      var result = [];

      baseEach(collection, function(value, index, collection) {
        if (predicate(value, index, collection)) {
          result.push(value);
        }
      });
      return result;
    }

    /**
     * The base implementation of `_.find`, `_.findLast`, `_.findKey`, and `_.findLastKey`,
     * without support for callback shorthands and `this` binding, which iterates
     * over `collection` using the provided `eachFunc`.
     *
     * @private
     * @param {Array|Object|string} collection The collection to search.
     * @param {Function} predicate The function invoked per iteration.
     * @param {Function} eachFunc The function to iterate over `collection`.
     * @param {boolean} [retKey=false] Specify returning the key of the found
     *  element instead of the element itself.
     * @returns {*} Returns the found element or its key, else `undefined`.
     */
    function baseFind(collection, predicate, eachFunc, retKey) {
      var result;

      eachFunc(collection, function(value, key, collection) {
        if (predicate(value, key, collection)) {
          result = retKey ? key : value;
          return false;
        }
      });
      return result;
    }

    /**
     * The base implementation of `_.flatten` with added support for restricting
     * flattening and specifying the start index.
     *
     * @private
     * @param {Array} array The array to flatten.
     * @param {boolean} [isDeep=false] Specify a deep flatten.
     * @param {boolean} [isStrict=false] Restrict flattening to arrays and `arguments` objects.
     * @param {number} [fromIndex=0] The index to start from.
     * @returns {Array} Returns the new flattened array.
     */
    function baseFlatten(array, isDeep, isStrict, fromIndex) {
      var index = (fromIndex || 0) - 1,
          length = array.length,
          resIndex = -1,
          result = [];

      while (++index < length) {
        var value = array[index];

        if (value && typeof value == 'object' && typeof value.length == 'number'
            && (isArray(value) || isArguments(value))) {
          // recursively flatten arrays (susceptible to call stack limits)
          if (isDeep) {
            value = baseFlatten(value, isDeep, isStrict);
          }
          var valIndex = -1,
              valLength = value.length;

          result.length += valLength;
          while (++valIndex < valLength) {
            result[++resIndex] = value[valIndex];
          }
        } else if (!isStrict) {
          result[++resIndex] = value;
        }
      }
      return result;
    }

    /**
     * The base implementation of `baseForIn` and `baseForOwn` which iterates
     * over `object` properties returned by `keysFunc` invoking `iteratee` for
     * each property. Iterator functions may exit iteration early by explicitly
     * returning `false`.
     *
     * @private
     * @param {Object} object The object to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @param {Function} keysFunc The function to get the keys of `object`.
     * @returns {Object} Returns `object`.
     */
    function baseFor(object, iteratee, keysFunc) {
      var index = -1,
          iterable = toObject(object),
          props = keysFunc(object),
          length = props.length;

      while (++index < length) {
        var key = props[index];
        if (iteratee(iterable[key], key, iterable) === false) {
          break;
        }
      }
      return object;
    }

    /**
     * This function is like `baseFor` except that it iterates over properties
     * in the opposite order.
     *
     * @private
     * @param {Object} object The object to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @param {Function} keysFunc The function to get the keys of `object`.
     * @returns {Object} Returns `object`.
     */
    function baseForRight(object, iteratee, keysFunc) {
      var iterable = toObject(object),
          props = keysFunc(object),
          length = props.length;

      while (length--) {
        var key = props[length];
        if (iteratee(iterable[key], key, iterable) === false) {
          break;
        }
      }
      return object;
    }

    /**
     * The base implementation of `_.forIn` without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Object} object The object to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Object} Returns `object`.
     */
    function baseForIn(object, iteratee) {
      return baseFor(object, iteratee, keysIn);
    }

    /**
     * The base implementation of `_.forOwn` without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Object} object The object to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Object} Returns `object`.
     */
    function baseForOwn(object, iteratee) {
      return baseFor(object, iteratee, keys);
    }

    /**
     * The base implementation of `_.forOwnRight` without support for callback
     * shorthands and `this` binding.
     *
     * @private
     * @param {Object} object The object to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Object} Returns `object`.
     */
    function baseForOwnRight(object, iteratee) {
      return baseForRight(object, iteratee, keys);
    }

    /**
     * The base implementation of `_.functions` which creates an array of
     * `object` function property names filtered from those provided.
     *
     * @private
     * @param {Object} object The object to inspect.
     * @param {Array} props The property names to filter.
     * @returns {Array} Returns the new array of filtered property names.
     */
    function baseFunctions(object, props) {
      var index = -1,
          length = props.length,
          resIndex = -1,
          result = [];

      while (++index < length) {
        var key = props[index];
        if (isFunction(object[key])) {
          result[++resIndex] = key;
        }
      }
      return result;
    }

    /**
     * The base implementation of `_.isEqual`, without support for `thisArg`
     * binding, which allows partial "_.where" style comparisons.
     *
     * @private
     * @param {*} value The value to compare to `other`.
     * @param {*} other The value to compare to `value`.
     * @param {Function} [customizer] The function to customize comparing values.
     * @param {boolean} [isWhere=false] Specify performing partial comparisons.
     * @param {Array} [stackA=[]] Tracks traversed `value` objects.
     * @param {Array} [stackB=[]] Tracks traversed `other` objects.
     * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
     */
    function baseIsEqual(value, other, customizer, isWhere, stackA, stackB) {
      var result = customizer && !stackA ? customizer(value, other) : undefined;
      if (typeof result != 'undefined') {
        return !!result;
      }
      // exit early for identical values
      if (value === other) {
        // treat `+0` vs. `-0` as not equal
        return value !== 0 || (1 / value == 1 / other);
      }
      var valType = typeof value,
          othType = typeof other;

      // exit early for unlike primitive values
      if (!(valType == 'number' && othType == 'number') && (value == null || other == null ||
          (valType != 'function' && valType != 'object' && othType != 'function' && othType != 'object'))) {
        return false;
      }
      var valClass = toString.call(value),
          valIsArg = valClass == argsClass,
          othClass = toString.call(other),
          othIsArg = othClass == argsClass;

      if (valIsArg) {
        valClass = objectClass;
      }
      if (othIsArg) {
        othClass = objectClass;
      }
      var valIsArr = arrayLikeClasses[valClass],
          valIsErr = valClass == errorClass,
          valIsObj = valClass == objectClass,
          othIsObj = othClass == objectClass;

      var isSameClass = valClass == othClass;
      if (isSameClass && valIsArr) {
        var valLength = value.length,
            othLength = other.length;

        if (valLength != othLength && !(isWhere && othLength > valLength)) {
          return false;
        }
      }
      else {
        // unwrap any `lodash` wrapped values
        var valWrapped = valIsObj && hasOwnProperty.call(value, '__wrapped__'),
            othWrapped = othIsObj && hasOwnProperty.call(other, '__wrapped__');

        if (valWrapped || othWrapped) {
          return baseIsEqual(valWrapped ? value.value() : value, othWrapped ? other.value() : other, customizer, isWhere, stackA, stackB);
        }
        if (!isSameClass) {
          return false;
        }
        if (valIsErr || valIsObj) {
          // in older versions of Opera, `arguments` objects have `Array` constructors
          var valCtor = valIsArg ? Object : value.constructor,
              othCtor = othIsArg ? Object : other.constructor;

          if (valIsErr) {
            // error objects of different types are not equal
            if (valCtor.prototype.name != othCtor.prototype.name) {
              return false;
            }
          }
          else {
            var valHasCtor = !valIsArg && hasOwnProperty.call(value, 'constructor'),
                othHasCtor = !othIsArg && hasOwnProperty.call(other, 'constructor');

            if (valHasCtor != othHasCtor) {
              return false;
            }
            if (!valHasCtor) {
              // non `Object` object instances with different constructors are not equal
              if (valCtor != othCtor && ('constructor' in value && 'constructor' in other) &&
                  !(typeof valCtor == 'function' && valCtor instanceof valCtor &&
                    typeof othCtor == 'function' && othCtor instanceof othCtor)) {
                return false;
              }
            }
          }
          var valProps = valIsErr ? ['message', 'name'] : keys(value),
              othProps = valIsErr ? valProps : keys(other);

          if (valIsArg) {
            valProps.push('length');
          }
          if (othIsArg) {
            othProps.push('length');
          }
          valLength = valProps.length;
          othLength = othProps.length;
          if (valLength != othLength && !isWhere) {
            return false;
          }
        }
        else {
          switch (valClass) {
            case boolClass:
            case dateClass:
              // coerce dates and booleans to numbers, dates to milliseconds and booleans
              // to `1` or `0` treating invalid dates coerced to `NaN` as not equal
              return +value == +other;

            case numberClass:
              // treat `NaN` vs. `NaN` as equal
              return (value != +value)
                ? other != +other
                // but treat `-0` vs. `+0` as not equal
                : (value == 0 ? ((1 / value) == (1 / other)) : value == +other);

            case regexpClass:
            case stringClass:
              // coerce regexes to strings (http://es5.github.io/#x15.10.6.4) and
              // treat strings primitives and string objects as equal
              return value == String(other);
          }
          return false;
        }
      }
      // assume cyclic structures are equal
      // the algorithm for detecting cyclic structures is adapted from ES 5.1
      // section 15.12.3, abstract operation `JO` (http://es5.github.io/#x15.12.3)
      stackA || (stackA = []);
      stackB || (stackB = []);

      var index = stackA.length;
      while (index--) {
        if (stackA[index] == value) {
          return stackB[index] == other;
        }
      }
      // add `value` and `other` to the stack of traversed objects
      stackA.push(value);
      stackB.push(other);

      // recursively compare objects and arrays (susceptible to call stack limits)
      result = true;
      if (valIsArr) {
        // deep compare the contents, ignoring non-numeric properties
        while (result && ++index < valLength) {
          var valValue = value[index];
          if (isWhere) {
            var othIndex = othLength;
            while (othIndex--) {
              result = baseIsEqual(valValue, other[othIndex], customizer, isWhere, stackA, stackB);
              if (result) {
                break;
              }
            }
          } else {
            var othValue = other[index];
            result = customizer ? customizer(valValue, othValue, index) : undefined;
            if (typeof result == 'undefined') {
              result = baseIsEqual(valValue, othValue, customizer, isWhere, stackA, stackB);
            }
          }
        }
      }
      else {
        while (result && ++index < valLength) {
          var key = valProps[index];
          result = valIsErr || hasOwnProperty.call(other, key);

          if (result) {
            valValue = value[key];
            othValue = other[key];
            result = customizer ? customizer(valValue, othValue, key) : undefined;
            if (typeof result == 'undefined') {
              result = baseIsEqual(valValue, othValue, customizer, isWhere, stackA, stackB);
            }
          }
        }
      }
      stackA.pop();
      stackB.pop();

      return !!result;
    }

    /**
     * The base implementation of `_.invoke` which requires additional arguments
     * be provided as an array of arguments rather than individually.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|string} methodName The name of the method to invoke or
     *  the function invoked per iteration.
     * @param {Array} [args] The arguments to invoke the method with.
     * @returns {Array} Returns the array of results.
     */
    function baseInvoke(collection, methodName, args) {
      var index = -1,
          isFunc = typeof methodName == 'function',
          length = collection ? collection.length : 0,
          result = [];

      if (typeof length == 'number' && length > -1 && length <= MAX_SAFE_INTEGER) {
        result.length = length;
      }
      baseEach(collection, function(value) {
        var func = isFunc ? methodName : (value != null && value[methodName]);
        result[++index] = func ? func.apply(value, args) : undefined;
      });
      return result;
    }

    /**
     * The base implementation of `_.map` without support for callback shorthands
     * or `this` binding.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @returns {Array} Returns the new mapped array.
     */
    function baseMap(collection, iteratee) {
      var result = [];

      baseEach(collection, function(value, key, collection) {
        result.push(iteratee(value, key, collection));
      });
      return result;
    }

    /**
     * The base implementation of `_.merge` without support for argument juggling,
     * multiple sources, and `this` binding.
     *
     * @private
     * @param {Object} object The destination object.
     * @param {Object} source The source object.
     * @param {Function} [customizer] The function to customize merging properties.
     * @param {Array} [stackA=[]] Tracks traversed source objects.
     * @param {Array} [stackB=[]] Associates values with source counterparts.
     * @returns {Object} Returns the destination object.
     */
    function baseMerge(object, source, customizer, stackA, stackB) {
      var isSrcArr = isArrayLike(source);

      (isSrcArr ? arrayEach : baseForOwn)(source, function(srcValue, key, source) {
        var isArr = srcValue && isArrayLike(srcValue),
            isObj = srcValue && isPlainObject(srcValue),
            value = object[key];

        if (!(isArr || isObj)) {
          result = customizer ? customizer(value, srcValue, key, object, source) : undefined;
          if (typeof result == 'undefined') {
            result = srcValue;
          }
          if (isSrcArr || typeof result != 'undefined') {
            object[key] = result;
          }
          return;
        }
        // avoid merging previously merged cyclic sources
        stackA || (stackA = []);
        stackB || (stackB = []);

        var length = stackA.length;
        while (length--) {
          if (stackA[length] == srcValue) {
            object[key] = stackB[length];
            return;
          }
        }
        var result = customizer ? customizer(value, srcValue, key, object, source) : undefined,
            isDeep = typeof result == 'undefined';

        if (isDeep) {
          result = isArr
            ? (isArray(value) ? value : [])
            : (isPlainObject(value) ? value : {});
        }
        // add the source value to the stack of traversed objects
        // and associate it with its merged value
        stackA.push(srcValue);
        stackB.push(result);

        // recursively merge objects and arrays (susceptible to call stack limits)
        if (isDeep) {
          baseMerge(result, srcValue, customizer, stackA, stackB);
        }
        object[key] = result;
      });
      return object;
    }

    /**
     * The base implementation of `_.partial` and `_.partialRight` which accepts
     * an array of arguments to partially apply and handles resolving the arity
     * of `func`.
     *
     * @private
     * @param {Function} func The function to partially apply arguments to.
     * @param {number} bitmask The bitmask of flags to compose.
     * @param {Array} args The arguments to be partially applied.
     * @param {*} [thisArg] The `this` binding of `func`.
     * @returns {Function} Returns the new partially applied function.
     */
    function basePartial(func, bitmask, args, holders, thisArg) {
      if (func) {
        var data = getData(func),
            arity = data ? data[2] : func.length;

        arity = nativeMax(arity - args.length, 0);
      }
      return (bitmask & PARTIAL_FLAG)
        ? createWrapper(func, bitmask, arity, thisArg, args, holders)
        : createWrapper(func, bitmask, arity, thisArg, null, null, args, holders);
    }

    /**
     * The base implementation of `_.pullAt` without support for individual
     * index arguments.
     *
     * @private
     * @param {Array} array The array to modify.
     * @param {number[]} indexes The indexes of elements to remove.
     * @returns {Array} Returns the new array of removed elements.
     */
    function basePullAt(array, indexes) {
      var length = indexes.length,
          result = baseAt(array, indexes);

      indexes.sort(baseCompareAscending);
      while (length--) {
        var index = parseFloat(indexes[length]);
        if (index != previous && index > -1 && index % 1 == 0) {
          var previous = index;
          splice.call(array, index, 1);
        }
      }
      return result;
    }

    /**
     * The base implementation of `_.random` without support for argument juggling
     * and returning floating-point numbers.
     *
     * @private
     * @param {number} min The minimum possible value.
     * @param {number} max The maximum possible value.
     * @returns {number} Returns the random number.
     */
    function baseRandom(min, max) {
      return min + floor(nativeRandom() * (max - min + 1));
    }

    /**
     * The base implementation of `_.reduce` and `_.reduceRight` without support
     * for callback shorthands or `this` binding, which iterates over `collection`
     * usingthe provided `eachFunc`.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} iteratee The function invoked per iteration.
     * @param {*} accumulator The initial value.
     * @param {boolean} initFromCollection Specify using the first or last element
     *  of `collection` as the initial value.
     * @param {Function} eachFunc The function to iterate over `collection`.
     * @returns {*} Returns the accumulated value.
     */
    function baseReduce(collection, iteratee, accumulator, initFromCollection, eachFunc) {
      eachFunc(collection, function(value, index, collection) {
        accumulator = initFromCollection
          ? (initFromCollection = false, value)
          : iteratee(accumulator, value, index, collection)
      });
      return accumulator;
    }

    /**
     * The base implementation of `setData` without support for hot loop detection.
     *
     * @private
     * @param {Function} func The function to associate metadata with.
     * @param {*} data The metadata.
     * @returns {Function} Returns `func`.
     */
    var baseSetData = !metaMap ? identity : function(func, data) {
      metaMap.set(func, data);
      return func;
    };

    /**
     * The base implementation of `_.some` without support for callback shorthands
     * or `this` binding.
     *
     * @private
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} predicate The function invoked per iteration.
     * @returns {boolean} Returns `true` if any element passes the predicate check,
     *  else `false`.
     */
    function baseSome(collection, predicate) {
      var result;

      baseEach(collection, function(value, index, collection) {
        result = predicate(value, index, collection);
        return !result;
      });
      return !!result;
    }

    /**
     * The base implementation of `_.sortedIndex` and `_.sortedLastIndex` without
     * support for callback shorthands and `this` binding.
     *
     * @private
     * @param {Array} array The array to inspect.
     * @param {*} value The value to evaluate.
     * @param {Function} iteratee The function invoked per iteration.
     * @param {boolean} [retHighest=false] Specify returning the highest, instead
     *  of the lowest, index at which a value should be inserted into `array`.
     * @returns {number} Returns the index at which `value` should be inserted
     *  into `array`.
     */
    function baseSortedIndex(array, value, iteratee, retHighest) {
      var low = 0,
          high = array ? array.length : low;

      value = iteratee(value);

      var valIsNaN = value !== value,
          valIsUndef = typeof value == 'undefined';

      while (low < high) {
        var mid = floor((low + high) / 2),
            computed = iteratee(array[mid]),
            isReflexive = computed === computed;

        if (valIsNaN) {
          var setLow = isReflexive || retHighest;
        } else if (valIsUndef) {
          setLow = isReflexive && (retHighest || typeof computed != 'undefined');
        } else {
          setLow = retHighest ? (computed <= value) : (computed < value);
        }
        if (setLow) {
          low = mid + 1;
        } else {
          high = mid;
        }
      }
      return nativeMin(high, MAX_ARRAY_INDEX);
    }

    /**
     * The base implementation of `_.uniq` without support for callback shorthands
     * and `this` binding.
     *
     * @private
     * @param {Array} array The array to inspect.
     * @param {Function} [iteratee] The function invoked per iteration.
     * @returns {Array} Returns the new duplicate-value-free array.
     */
    function baseUniq(array, iteratee) {
      var index = -1,
          indexOf = getIndexOf(),
          length = array.length,
          prereq = indexOf == baseIndexOf,
          isLarge = prereq && createCache && length >= 200,
          isCommon = prereq && !isLarge,
          result = [];

      if (isLarge) {
        var seen = createCache();
        indexOf = cacheIndexOf;
      } else {
        seen = iteratee ? [] : result;
      }
      outer:
      while (++index < length) {
        var value = array[index],
            computed = iteratee ? iteratee(value, index, array) : value;

        if (isCommon && value === value) {
          var seenIndex = seen.length;
          while (seenIndex--) {
            if (seen[seenIndex] === computed) {
              continue outer;
            }
          }
          if (iteratee) {
            seen.push(computed);
          }
          result.push(value);
        }
        else if (indexOf(seen, computed) < 0) {
          if (iteratee || isLarge) {
            seen.push(computed);
          }
          result.push(value);
        }
      }
      return result;
    }

    /**
     * The base implementation of `_.values` and `_.valuesIn` which creates an
     * array of `object` property values corresponding to the property names
     * returned by `keysFunc`.
     *
     * @private
     * @param {Object} object The object to inspect.
     * @param {Function} keysFunc The function to get the keys of `object`.
     * @returns {Object} Returns the array of property values.
     */
    function baseValues(object, keysFunc) {
      var index = -1,
          props = keysFunc(object),
          length = props.length,
          result = Array(length);

      while (++index < length) {
        result[index] = object[props[index]];
      }
      return result;
    }

    /**
     * Creates a clone of the given array buffer.
     *
     * @private
     * @param {ArrayBuffer} buffer The array buffer to clone.
     * @returns {ArrayBuffer} Returns the cloned array buffer.
     */
    function bufferClone(buffer) {
      return bufferSlice.call(buffer, 0);
    }
    if (!bufferSlice) {
      // PhantomJS has `ArrayBuffer` and `Uint8Array` but not `Float64Array`
      bufferClone = !(ArrayBuffer && Uint8Array) ? identity : function(buffer) {
        var byteLength = buffer.byteLength,
            floatLength = Float64Array ? floor(byteLength / FLOAT64_BYTES_PER_ELEMENT) : 0,
            offset = floatLength * FLOAT64_BYTES_PER_ELEMENT,
            result = new ArrayBuffer(byteLength);

        if (floatLength) {
          var view = new Float64Array(result, 0, floatLength);
          view.set(new Float64Array(buffer, 0, floatLength));
        }
        if (byteLength != offset) {
          view = new Uint8Array(result, offset);
          view.set(new Uint8Array(buffer, offset));
        }
        return result;
      };
    }

    /**
     * Creates an array that is the composition of partially applied arguments,
     * placeholders, and provided arguments into a single array of arguments.
     *
     * @private
     * @param {Array} partialArgs The arguments to prepend to those provided.
     * @param {Array} partialHolders The `partialArgs` placeholder indexes.
     * @param {Array|Object} args The provided arguments.
     * @returns {Array} Returns the new array of composed arguments.
     */
    function composeArgs(partialArgs, partialHolders, args) {
      var holdersLength = partialHolders.length,
          argsIndex = -1,
          argsLength = nativeMax(args.length - holdersLength, 0),
          leftIndex = -1,
          leftLength = partialArgs.length,
          result = Array(argsLength + leftLength);

      while (++leftIndex < leftLength) {
        result[leftIndex] = partialArgs[leftIndex];
      }
      while (++argsIndex < holdersLength) {
        result[partialHolders[argsIndex]] = args[argsIndex];
      }
      while (argsLength--) {
        result[leftIndex++] = args[argsIndex++];
      }
      return result;
    }

    /**
     * This function is like `composeArgs` except that the arguments composition
     * is tailored for `_.partialRight`.
     *
     * @private
     * @param {Array} partialRightArgs The arguments to append to those provided.
     * @param {Array} partialHolders The `partialRightArgs` placeholder indexes.
     * @param {Array|Object} args The provided arguments.
     * @returns {Array} Returns the new array of composed arguments.
     */
    function composeArgsRight(partialRightArgs, partialRightHolders, args) {
      var holdersIndex = -1,
          holdersLength = partialRightHolders.length,
          argsIndex = -1,
          argsLength = nativeMax(args.length - holdersLength, 0),
          rightIndex = -1,
          rightLength = partialRightArgs.length,
          result = Array(argsLength + rightLength);

      while (++argsIndex < argsLength) {
        result[argsIndex] = args[argsIndex];
      }
      var pad = argsIndex;
      while (++rightIndex < rightLength) {
        result[pad + rightIndex] = partialRightArgs[rightIndex];
      }
      while (++holdersIndex < holdersLength) {
        result[pad + partialRightHolders[holdersIndex]] = args[argsIndex++];
      }
      return result;
    }

    /**
     * Creates a function that aggregates a collection, creating an accumulator
     * object composed from the results of running each element in the collection
     * through `iteratee`. The given setter function sets the keys and values of
     * the accumulator object. If `initializer` is provided it is used to initialize
     * the accumulator object.
     *
     * @private
     * @param {Function} setter The function to set keys and values of the accumulator object.
     * @param {Function} [initializer] The function to initialize the accumulator object.
     * @returns {Function} Returns the new aggregator function.
     */
    function createAggregator(setter, initializer) {
      return function(collection, iteratee, thisArg) {
        iteratee = getCallback(iteratee, thisArg, 3);

        var result = initializer ? initializer() : {};
        if (isArray(collection)) {
          var index = -1,
              length = collection.length;

          while (++index < length) {
            var value = collection[index];
            setter(result, value, iteratee(value, index, collection), collection);
          }
        } else {
          baseEach(collection, function(value, key, collection) {
            setter(result, value, iteratee(value, key, collection), collection);
          });
        }
        return result;
      };
    }

    /**
     * Creates a function that assigns properties of source object(s) to a given
     * destination object.
     *
     * @private
     * @param {Function} assigner The function to handle assigning values.
     * @returns {Function} Returns the new assigner function.
     */
    function createAssigner(assigner) {
      return function() {
        var length = arguments.length,
            object = arguments[0];

        if (length < 2 || object == null) {
          return object;
        }
        if (length > 3 && isIterateeCall(arguments[1], arguments[2], arguments[3])) {
          length = 2;
        }
        // juggle arguments
        if (length > 3 && typeof arguments[length - 2] == 'function') {
          var customizer = baseCallback(arguments[--length - 1], arguments[length--], 5);
        } else if (length > 2 && typeof arguments[length - 1] == 'function') {
          customizer = arguments[--length];
        }
        var index = 0;
        while (++index < length) {
          assigner(object, arguments[index], customizer);
        }
        return object;
      };
    }

    /**
     * Creates a function that wraps `func` and invokes it with the `this`
     * binding of `thisArg`.
     *
     * @private
     * @param {Function} func The function to bind.
     * @param {*} [thisArg] The `this` binding of `func`.
     * @returns {Function} Returns the new wrapped function.
     */
    function createBindWrapper(func, thisArg) {
      var Ctor = createCtorWrapper(func);

      function wrapper() {
        return (this instanceof wrapper ? Ctor : func).apply(thisArg, arguments);
      }
      return wrapper;
    }

    /**
     * Creates a cache object to optimize linear searches of large arrays.
     *
     * @private
     * @param {Array} [array=[]] The array to search.
     * @returns {Object} Returns the new cache object.
     */
    var createCache = Set && function(array) {
      var cache = new Set,
          length = array ? array.length : 0;

      cache.push = cache.add;
      while (length--) {
        cache.push(array[length]);
      }
      return cache;
    };

    /**
     * Creates a function that produces compound words out of the words in a
     * given string.
     *
     * @private
     * @param {Function} callback The function invoked to combine each word.
     * @returns {Function} Returns the new compounder function.
     */
    function createCompounder(callback) {
      return function(string) {
        var index = -1,
            array = words(deburr(string)),
            length = array.length,
            result = '';

        while (++index < length) {
          result = callback(result, array[index], index, words);
        }
        return result;
      };
    }

    /**
     * Creates a function that produces an instance of `Ctor` regardless of
     * whether it was invoked as part of a `new` expression or by `call` or `apply`.
     *
     * @private
     * @param {Function} Ctor The constructor to wrap.
     * @returns {Function} Returns the new function.
     */
    function createCtorWrapper(Ctor) {
      return function() {
        var thisBinding = baseCreate(Ctor.prototype),
            result = Ctor.apply(thisBinding, arguments);

        // mimic the constructor's `return` behavior
        // http://es5.github.io/#x13.2.2
        return isObject(result) ? result : thisBinding;
      };
    }

    /**
     * Creates a function that wraps `func` and invokes it with optional `this`
     * binding of, partial application, and currying.
     *
     * @private
     * @param {Function|string} func The function or method name to reference.
     * @param {number} bitmask The bitmask of flags. See `createWrapper` for more details.
     * @param {number} arity The arity of `func`.
     * @param {*} [thisArg] The `this` binding of `func`.
     * @param {Array} [partialArgs] The arguments to prepend to those provided to the new function.
     * @param {Array} [partialHolders] The `partialArgs` placeholder indexes.
     * @param {Array} [partialRightArgs] The arguments to append to those provided to the new function.
     * @param {Array} [partialRightHolders] The `partialRightArgs` placeholder indexes.
     * @returns {Function} Returns the new function.
     */
    function createHybridWrapper(func, bitmask, arity, thisArg, partialArgs, partialHolders, partialRightArgs, partialRightHolders) {
      var isBind = bitmask & BIND_FLAG,
          isBindKey = bitmask & BIND_KEY_FLAG,
          isCurry = bitmask & CURRY_FLAG,
          isCurryRight = bitmask & CURRY_RIGHT_FLAG,
          isCurryBound = bitmask & CURRY_BOUND_FLAG;

      var Ctor = !isBindKey && createCtorWrapper(func),
          key = func;

      function wrapper() {
        var length = arguments.length,
            index = length,
            args = Array(length);

        while (index--) {
          args[index] = arguments[index];
        }
        if (partialArgs) {
          args = composeArgs(partialArgs, partialHolders, args);
        }
        if (partialRightArgs) {
          args = composeArgsRight(partialRightArgs, partialRightHolders, args);
        }
        if (isCurry || isCurryRight) {
          var placeholder = wrapper.placeholder,
              holders = replaceHolders(args, placeholder);

          length -= holders.length;
          if (length < arity) {
            var newArity = nativeMax(arity - length, 0),
                newPartialArgs = isCurry ? args : null,
                newPartialHolders = isCurry ? holders : null,
                newPartialRightArgs = isCurry ? null : args,
                newPartialRightHolders = isCurry ? null : holders;

            bitmask |= (isCurry ? PARTIAL_FLAG : PARTIAL_RIGHT_FLAG);
            bitmask &= ~(isCurry ? PARTIAL_RIGHT_FLAG : PARTIAL_FLAG);

            if (!isCurryBound) {
              bitmask &= ~(BIND_FLAG | BIND_KEY_FLAG);
            }
            var result = createHybridWrapper(func, bitmask, newArity, thisArg, newPartialArgs, newPartialHolders, newPartialRightArgs, newPartialRightHolders);
            result.placeholder = placeholder;
            return setData(result, [func, bitmask, newArity, thisArg, newPartialArgs, newPartialHolders, newPartialRightArgs, newPartialRightHolders]);
          }
        }
        var thisBinding = isBind ? thisArg : this;
        if (isBindKey) {
          func = thisBinding[key];
        }
        return (this instanceof wrapper ? (Ctor || createCtorWrapper(func)) : func).apply(thisBinding, args);
      }
      return wrapper;
    }

    /**
     * Creates the pad required for `string` based on the given padding length.
     * The `chars` string may be truncated if the number of padding characters
     * exceeds the padding length.
     *
     * @private
     * @param {string} string The string to create padding for.
     * @param {number} [length=0] The padding length.
     * @param {string} [chars=' '] The string used as padding.
     * @returns {string} Returns the pad for `string`.
     */
    function createPad(string, length, chars) {
      var strLength = string.length;
      length = +length;

      if (strLength >= length || !nativeIsFinite(length)) {
        return '';
      }
      var padLength = length - strLength;
      chars = chars == null ? ' ' : String(chars);
      return repeat(chars, ceil(padLength / chars.length)).slice(0, padLength);
    }

    /**
     * Creates a function that wraps `func` and invokes it with the optional `this`
     * binding of `thisArg` and the `partialArgs` prepended to those provided to
     * the wrapper.
     *
     * @private
     * @param {Function} func The function to partially apply arguments to.
     * @param {number} bitmask The bitmask of flags. See `createWrapper` for more details.
     * @param {Array} partialArgs The arguments to prepend to those provided to the new function.
     * @param {*} [thisArg] The `this` binding of `func`.
     * @returns {Function} Returns the new bound function.
     */
    function createPartialWrapper(func, bitmask, partialArgs, thisArg) {
      var isBind = bitmask & BIND_FLAG,
          Ctor = createCtorWrapper(func);

      function wrapper() {
        // avoid `arguments` object use disqualifying optimizations by
        // converting it to an array before passing it to `composeArgs`
        var argsIndex = -1,
            argsLength = arguments.length,
            leftIndex = -1,
            leftLength = partialArgs.length,
            args = Array(argsLength + leftLength);

        while (++leftIndex < leftLength) {
          args[leftIndex] = partialArgs[leftIndex];
        }
        while (argsLength--) {
          args[leftIndex++] = arguments[++argsIndex];
        }
        return (this instanceof wrapper ? Ctor : func).apply(isBind ? thisArg : this, args);
      }
      return wrapper;
    }

    /**
     * Creates a function that either curries or invokes `func` with optional
     * `this` binding and partially applied arguments.
     *
     * @private
     * @param {Function|string} func The function or method name to reference.
     * @param {number} bitmask The bitmask of flags.
     *  The bitmask may be composed of the following flags:
     *   1  - `_.bind`
     *   2  - `_.bindKey`
     *   4  - `_.curry`
     *   8  - `_.curryRight`
     *   16 - `_.curry` or `_.curryRight` of a bound function
     *   32 - `_.partial`
     *   64 - `_.partialRight`
     * @param {number} arity The arity of `func`.
     * @param {*} [thisArg] The `this` binding of `func`.
     * @param {Array} [partialArgs] The arguments to prepend to those provided to the new function.
     * @param {Array} [partialHolders] The `partialArgs` placeholder indexes.
     * @param {Array} [partialRightArgs] The arguments to append to those provided to the new function.
     * @param {Array} [partialRightHolders] The `partialRightArgs` placeholder indexes.
     * @returns {Function} Returns the new function.
     */
    function createWrapper(func, bitmask, arity, thisArg, partialArgs, partialHolders, partialRightArgs, partialRightHolders) {
      var isBindKey = bitmask & BIND_KEY_FLAG;
      if (!isBindKey && !isFunction(func)) {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      var isPartial = bitmask & PARTIAL_FLAG;
      if (isPartial && !partialArgs.length) {
        bitmask &= ~PARTIAL_FLAG;
        isPartial = false;
        partialArgs = partialHolders = null;
      }
      var isPartialRight = bitmask & PARTIAL_RIGHT_FLAG;
      if (isPartialRight && !partialRightArgs.length) {
        bitmask &= ~PARTIAL_RIGHT_FLAG;
        isPartialRight = false;
        partialRightArgs = partialRightHolders = null;
      }
      var data = (data = !isBindKey && getData(func)) && data !== true && data;
      if (data) {
        var funcBitmask = data[1],
            funcIsBind = funcBitmask & BIND_FLAG,
            isBind = bitmask & BIND_FLAG;

        // use metadata `func` and merge bitmasks
        func = data[0];
        bitmask |= funcBitmask;

        // use metadata `arity` if not provided
        if (arity == null) {
          arity = data[2];
        }
        // use metadata `thisArg` if available
        if (funcIsBind) {
          thisArg = data[3];
        }
        // set if currying a bound function
        if (!isBind && funcIsBind) {
          bitmask |= CURRY_BOUND_FLAG;
        }
        // append partial left arguments
        var funcArgs = data[4];
        if (funcArgs) {
          var funcHolders = data[5];
          partialArgs = isPartial ? composeArgs(funcArgs, funcHolders, partialArgs) : baseSlice(funcArgs);
          partialHolders = isPartial ? replaceHolders(partialArgs, PLACEHOLDER) : baseSlice(funcHolders);
        }
        // prepend partial right arguments
        funcArgs = data[6];
        if (funcArgs) {
          funcHolders = data[7];
          partialRightArgs = isPartialRight ? composeArgsRight(funcArgs, funcHolders, partialRightArgs) : baseSlice(funcArgs);
          partialRightHolders = isPartialRight ? replaceHolders(partialRightArgs, PLACEHOLDER) : baseSlice(funcHolders);
        }
      }
      if (arity == null) {
        arity = isBindKey ? 0 : func.length;
      }
      if (bitmask == BIND_FLAG) {
        var result = createBindWrapper(func, thisArg);
      } else if ((bitmask == PARTIAL_FLAG || bitmask == (BIND_FLAG | PARTIAL_FLAG)) && !partialHolders.length) {
        result = createPartialWrapper(func, bitmask, partialArgs, thisArg);
      } else {
        result = createHybridWrapper(func, bitmask, arity, thisArg, partialArgs, partialHolders, partialRightArgs, partialRightHolders);
      }
      var setter = data ? baseSetData : setData;
      return setter(result, [func, bitmask, arity, thisArg, partialArgs, partialHolders, partialRightArgs, partialRightHolders]);
    }

    /**
     * Gets the appropriate "callback" function. If the `_.callback` method is
     * customized this function returns the custom method, otherwise it returns
     * the `baseCallback` function. If arguments are provided the chosen function
     * is invoked with them and its result is returned.
     *
     * @private
     * @returns {Function} Returns the chosen function or its result.
     */
    function getCallback(func, thisArg, argCount) {
      var result = lodash.callback || callback;
      result = result === callback ? baseCallback : result;
      return argCount ? result(func, thisArg, argCount) : result;
    }

    /**
     * Gets metadata for `func`.
     *
     * @private
     * @param {Function} func The function to query.
     * @returns {*} Returns the metadata for `func`.
     */
    var getData = !metaMap ? noop : function(func) {
      return metaMap.get(func);
    };

    /**
     * Gets the appropriate "indexOf" function. If the `_.indexOf` method is
     * customized this function returns the custom method, otherwise it returns
     * the `baseIndexOf` function. If arguments are provided the chosen function
     * is invoked with them and its result is returned.
     *
     * @private
     * @returns {Function|number} Returns the chosen function or its result.
     */
    function getIndexOf(collection, target, fromIndex) {
      var result = lodash.indexOf || indexOf;
      result = result === indexOf ? baseIndexOf : result;
      return collection ? result(collection, target, fromIndex) : result;
    }

    /**
     * Initializes an array clone.
     *
     * @private
     * @param {*} value The value to clone.
     * @param {boolean} [isDeep=false] Specify a deep clone.
     * @returns {*} Returns the initialized clone value.
     */
    function initArrayClone(array, isDeep) {
      var index = -1,
          length = array.length,
          result = array.constructor(length);

      if (!isDeep) {
        while (++index < length) {
          result[index] = array[index];
        }
      }
      // add array properties assigned by `RegExp#exec`
      if (length && typeof array[0] == 'string' && hasOwnProperty.call(array, 'index')) {
        result.index = array.index;
        result.input = array.input;
      }
      return result;
    }

    /**
     * Initializes an object clone.
     *
     * @private
     * @param {*} value The value to clone.
     * @param {boolean} [isDeep=false] Specify a deep clone.
     * @returns {*} Returns the initialized clone value.
     */
    function initObjectClone(object, isDeep) {
      var className = toString.call(object);
      if (!cloneableClasses[className]) {
        return object;
      }
      var Ctor = object.constructor,
          isArgs = className == argsClass,
          isObj = className == objectClass;

      if (isObj && !(typeof Ctor == 'function' && Ctor instanceof Ctor)) {
        Ctor = Object;
      }
      if (isArgs || isObj) {
        var result = isDeep ? new Ctor : baseAssign(new Ctor, object);
        if (isArgs) {
          result.length = object.length;
        }
        return result;
      }
      switch (className) {
        case arrayBufferClass:
          return bufferClone(object);

        case boolClass:
        case dateClass:
          return new Ctor(+object);

        case float32Class: case float64Class:
        case int8Class: case int16Class: case int32Class:
        case uint8Class: case uint8ClampedClass: case uint16Class: case uint32Class:
          var buffer = object.buffer;
          return new Ctor(isDeep ? bufferClone(buffer) : buffer, object.byteOffset, object.length);

        case numberClass:
        case stringClass:
          return new Ctor(object);

        case regexpClass:
          result = Ctor(object.source, reFlags.exec(object));
          result.lastIndex = object.lastIndex;
      }
      return result;
    }

    /**
     * Checks if `value` is an array-like object.
     *
     * @private
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is an array-like object, else `false`.
     */
    function isArrayLike(value) {
      return (value && typeof value == 'object' && typeof value.length == 'number' &&
        arrayLikeClasses[toString.call(value)]) || false;
    }

    /**
     * Checks if `value` is suitable for strict equality comparisons, i.e. `===`.
     *
     * @private
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` if suitable for strict
     *  equality comparisons, else `false`.
     */
    function isStrictComparable(value) {
      return value === value && (value === 0 ? ((1 / value) > 0) : !isObject(value));
    }

    /**
     * A specialized version of `_.pick` that picks `object` properties
     * specified by the `props` array.
     *
     * @private
     * @param {Object} object The source object.
     * @param {string[]} props The property names to pick.
     * @returns {Object} Returns the new object.
     */
    function pickByArray(object, props) {
      object = toObject(object);

      var index = -1,
          length = props.length,
          result = {};

      while (++index < length) {
        var key = props[index];
        if (key in object) {
          result[key] = object[key];
        }
      }
      return result;
    }

    /**
     * A specialized version of `_.pick` that picks `object` properties `predicate`
     * returns truthy for.
     *
     * @private
     * @param {Object} object The source object.
     * @param {Function} predicate The function invoked per iteration.
     * @returns {Object} Returns the new object.
     */
    function pickByCallback(object, predicate) {
      var result = {};

      baseForIn(object, function(value, key, object) {
        if (predicate(value, key, object)) {
          result[key] = value;
        }
      });
      return result;
    }

    /**
     * Sets metadata for `func`.
     *
     * **Note:** If this function becomes hot, i.e. is invoked a lot in a short
     * period of time, it will trip its breaker and transition to an identity
     * function to avoid garbage collection pauses.
     *
     * @private
     * @param {Function} func The function to associate metadata with.
     * @param {*} data The metadata.
     * @returns {Function} Returns `func`.
     */
    var setData = (function() {
      var count = 0,
          lastCalled = 0;

      return function(key, value) {
        var stamp = now ? now() : 0,
            remaining = HOT_SPAN - (stamp - lastCalled);

        lastCalled = stamp;
        if (remaining > 0) {
          if (++count >= HOT_COUNT) {
            return key;
          }
        } else {
          count = 0;
        }
        return baseSetData(key, value);
      };
    }());

    /**
     * A fallback implementation of `_.isPlainObject` which checks if `value`
     * is an object created by the `Object` constructor or has a `[[Prototype]]`
     * of `null`.
     *
     * @private
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is a plain object, else `false`.
     */
    function shimIsPlainObject(value) {
      var Ctor,
          result;

      // exit early for non `Object` objects
      if (!(value && typeof value == 'object' &&
            toString.call(value) == objectClass) ||
          (!hasOwnProperty.call(value, 'constructor') &&
            (Ctor = value.constructor, typeof Ctor == 'function' && !(Ctor instanceof Ctor)))) {
        return false;
      }
      // In most environments an object's own properties are iterated before
      // its inherited properties. If the last iterated property is an object's
      // own property then there are no inherited enumerable properties.
      baseForIn(value, function(value, key) {
        result = key;
      });
      return typeof result == 'undefined' || hasOwnProperty.call(value, result);
    }

    /**
     * A fallback implementation of `Object.keys` which creates an array of the
     * own enumerable property names of `object`.
     *
     * @private
     * @param {Object} object The object to inspect.
     * @returns {Array} Returns the array of property names.
     */
    function shimKeys(object) {
      var keyIndex,
          index = -1,
          props = keysIn(object),
          length = props.length,
          objLength = length && object.length,
          maxIndex = objLength - 1,
          result = [];

      var allowIndexes = typeof objLength == 'number' && objLength > 0 &&
        (isArray(object) || (support.nonEnumArgs && isArguments(object)));

      while (++index < length) {
        var key = props[index];
        if ((allowIndexes && (keyIndex = +key, keyIndex > -1 && keyIndex <= maxIndex && keyIndex % 1 == 0)) ||
            hasOwnProperty.call(object, key)) {
          result.push(key);
        }
      }
      return result;
    }

    /**
     * Converts `value` to an array-like object if it is not one.
     *
     * @private
     * @param {*} value The value to process.
     * @returns {Array|Object} Returns the array-like object.
     */
    function toIterable(value) {
      if (value == null) {
        return [];
      }
      var length = value.length;
      if (!(typeof length == 'number' && length > -1 && length <= MAX_SAFE_INTEGER)) {
        return values(value);
      }
      return isObject(value) ? value : Object(value);
    }

    /**
     * Converts `value` to an object if it is not one.
     *
     * @private
     * @param {*} value The value to process.
     * @returns {Object} Returns the object.
     */
    function toObject(value) {
      return isObject(value) ? value : Object(value);
    }

    /*------------------------------------------------------------------------*/

    /**
     * Creates an array of elements split into groups the length of `size`.
     * If `collection` can't be split evenly, the final chunk will be the remaining
     * elements.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to process.
     * @param {numer} [size=1] The length of each chunk.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Array} Returns the new array containing chunks.
     * @example
     *
     * _.chunk(['a', 'b', 'c', 'd'], 2);
     * // => [['a', 'b'], ['c', 'd']]
     *
     * _.chunk(['a', 'b', 'c', 'd'], 3);
     * // => [['a', 'b', 'c'], ['d']]
     */
    function chunk(array, size, guard) {
      var index = 0,
          length = array ? array.length : 0,
          resIndex = -1,
          result = [];

      size = (guard || size == null) ? 1 : nativeMax(+size || 1, 1);
      while (index < length) {
        result[++resIndex] = slice(array, index, (index += size));
      }
      return result;
    }

    /**
     * Creates an array with all falsey values removed. The values `false`, `null`,
     * `0`, `""`, `undefined`, and `NaN` are all falsey.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to compact.
     * @returns {Array} Returns the new array of filtered values.
     * @example
     *
     * _.compact([0, 1, false, 2, '', 3]);
     * // => [1, 2, 3]
     */
    function compact(array) {
      var index = -1,
          length = array ? array.length : 0,
          resIndex = -1,
          result = [];

      while (++index < length) {
        var value = array[index];
        if (value) {
          result[++resIndex] = value;
        }
      }
      return result;
    }

    /**
     * Creates an array excluding all values of the provided arrays using
     * `SameValueZero` for equality comparisons.
     *
     * **Note:** `SameValueZero` is like strict equality, e.g. `===`, except that
     * `NaN` matches `NaN`. See the [ES6 spec](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * for more details.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to inspect.
     * @param {...Array} [values] The arrays of values to exclude.
     * @returns {Array} Returns the new array of filtered values.
     * @example
     *
     * _.difference([1, 2, 3], [5, 2, 10]);
     * // => [1, 3]
     */
    function difference() {
      var index = -1,
          length = arguments.length;

      while (++index < length) {
        var value = arguments[index];
        if (isArray(value) || isArguments(value)) {
          break;
        }
      }
      return baseDifference(arguments[index], baseFlatten(arguments, false, true, ++index));
    }

    /**
     * Creates a slice of `array` with `n` elements dropped from the beginning.
     *
     * @static
     * @memberOf _
     * @type Function
     * @category Array
     * @param {Array} array The array to query.
     * @param {number} [n=1] The number of elements to drop.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.drop([1, 2, 3], 1);
     * // => [2, 3]
     *
     * _.drop([1, 2, 3], 2);
     * // => [3]
     *
     * _.drop([1, 2, 3], 5);
     * // => []
     *
     * _.drop([1, 2, 3], 0);
     * // => [1, 2, 3]
     */
    function drop(array, n, guard) {
      n = (guard || n == null) ? 1 : n;
      return slice(array, n < 0 ? 0 : n);
    }

    /**
     * Creates a slice of `array` with `n` elements dropped from the end.
     *
     * @static
     * @memberOf _
     * @type Function
     * @category Array
     * @param {Array} array The array to query.
     * @param {number} [n=1] The number of elements to drop.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.dropRight([1, 2, 3], 1);
     * // => [1, 2]
     *
     * _.dropRight([1, 2, 3], 2);
     * // => [1]
     *
     * _.dropRight([1, 2, 3], 5);
     * // => []
     *
     * _.dropRight([1, 2, 3], 0);
     * // => [1, 2, 3]
     */
    function dropRight(array, n, guard) {
      var length = array ? array.length : 0;
      n = (guard || n == null) ? 1 : n;
      n = length - (n || 0);
      return slice(array, 0, n < 0 ? 0 : n);
    }

    /**
     * Creates a slice of `array` excluding elements dropped from the end.
     * Elements are dropped until `predicate` returns falsey. The predicate is
     * bound to `thisArg` and invoked with three arguments; (value, index, array).
     *
     * If a property name is provided for `predicate` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `predicate` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @type Function
     * @category Array
     * @param {Array} array The array to query.
     * @param {Function|Object|string} [predicate=identity] The function invoked
     *  per element.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.dropRightWhile([1, 2, 3], function(n) { return n > 1; });
     * // => [1]
     *
     * var users = [
     *   { 'user': 'barney',  'employer': 'slate' },
     *   { 'user': 'fred',    'employer': 'slate', 'blocked': true },
     *   { 'user': 'pebbles', 'employer': 'na',    'blocked': true }
     * ];
     *
     * // using "_.pluck" callback shorthand
     * _.pluck(_.dropRightWhile(users, 'blocked'), 'user');
     * // => ['barney']
     *
     * // using "_.where" callback shorthand
     * _.pluck(_.dropRightWhile(users, { 'employer': 'na' }), 'user');
     * // => ['barney', 'fred']
     */
    function dropRightWhile(array, predicate, thisArg) {
      var length = array ? array.length : 0,
          index = length;

      predicate = getCallback(predicate, thisArg, 3);
      while (index-- && predicate(array[index], index, array)) {}
      return slice(array, 0, index + 1);
    }

    /**
     * Creates a slice of `array` excluding elements dropped from the beginning.
     * Elements are dropped until `predicate` returns falsey. The predicate is
     * bound to `thisArg` and invoked with three arguments; (value, index, array).
     *
     * If a property name is provided for `predicate` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `predicate` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @type Function
     * @category Array
     * @param {Array} array The array to query.
     * @param {Function|Object|string} [predicate=identity] The function invoked
     *  per element.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.dropWhile([1, 2, 3], function(n) { return n < 3; });
     * // => [3]
     *
     * var users = [
     *   { 'user': 'barney',  'employer': 'slate', 'blocked': true },
     *   { 'user': 'fred',    'employer': 'slate' },
     *   { 'user': 'pebbles', 'employer': 'na',    'blocked': true }
     * ];
     *
     * // using "_.pluck" callback shorthand
     * _.pluck(_.dropWhile(users, 'blocked'), 'user');
     * // => ['fred', 'pebbles']
     *
     * // using "_.where" callback shorthand
     * _.pluck(_.dropWhile(users, { 'employer': 'slate' }), 'user');
     * // => ['pebbles']
     */
    function dropWhile(array, predicate, thisArg) {
      var index = -1,
          length = array ? array.length : 0;

      predicate = getCallback(predicate, thisArg, 3);
      while (++index < length && predicate(array[index], index, array)) {}
      return slice(array, index);
    }

    /**
     * This method is like `_.find` except that it returns the index of the first
     * element `predicate` returns truthy for, instead of the element itself.
     *
     * If a property name is provided for `predicate` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `predicate` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to search.
     * @param {Function|Object|string} [predicate=identity] The function invoked
     *  per iteration. If a property name or object is provided it is used to
     *  create a "_.pluck" or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {number} Returns the index of the found element, else `-1`.
     * @example
     *
     * var users = [
     *   { 'user': 'barney',  'age': 36 },
     *   { 'user': 'fred',    'age': 40, 'blocked': true },
     *   { 'user': 'pebbles', 'age': 1 }
     * ];
     *
     * _.findIndex(users, function(chr) {
     *   return chr.age < 20;
     * });
     * // => 2
     *
     * // using "_.where" callback shorthand
     * _.findIndex(users, { 'age': 36 });
     * // => 0
     *
     * // using "_.pluck" callback shorthand
     * _.findIndex(users, 'blocked');
     * // => 1
     */
    function findIndex(array, predicate, thisArg) {
      var index = -1,
          length = array ? array.length : 0;

      predicate = getCallback(predicate, thisArg, 3);
      while (++index < length) {
        if (predicate(array[index], index, array)) {
          return index;
        }
      }
      return -1;
    }

    /**
     * This method is like `_.findIndex` except that it iterates over elements
     * of `collection` from right to left.
     *
     * If a property name is provided for `predicate` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `predicate` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to search.
     * @param {Function|Object|string} [predicate=identity] The function invoked
     *  per iteration. If a property name or object is provided it is used to
     *  create a "_.pluck" or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {number} Returns the index of the found element, else `-1`.
     * @example
     *
     * var users = [
     *   { 'user': 'barney',  'age': 36, 'blocked': true },
     *   { 'user': 'fred',    'age': 40 },
     *   { 'user': 'pebbles', 'age': 1,  'blocked': true }
     * ];
     *
     * _.findLastIndex(users, function(chr) {
     *   return chr.age > 30;
     * });
     * // => 1
     *
     * // using "_.where" callback shorthand
     * _.findLastIndex(users, { 'age': 36 });
     * // => 0
     *
     * // using "_.pluck" callback shorthand
     * _.findLastIndex(users, 'blocked');
     * // => 2
     */
    function findLastIndex(array, predicate, thisArg) {
      var length = array ? array.length : 0;

      predicate = getCallback(predicate, thisArg, 3);
      while (length--) {
        if (predicate(array[length], length, array)) {
          return length;
        }
      }
      return -1;
    }

    /**
     * Gets the first element of `array`.
     *
     * @static
     * @memberOf _
     * @alias head
     * @category Array
     * @param {Array} array The array to query.
     * @returns {*} Returns the first element of `array`.
     * @example
     *
     * _.first([1, 2, 3]);
     * // => 1
     *
     * _.first([]);
     * // => undefined
     */
    function first(array) {
      return array ? array[0] : undefined;
    }

    /**
     * Flattens a nested array. If `isDeep` is `true` the array is recursively
     * flattened, otherwise it is only flattened a single level.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to flatten.
     * @param {boolean} [isDeep=false] Specify a deep flatten.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Array} Returns the new flattened array.
     * @example
     *
     * _.flatten([1, [2], [3, [[4]]]]);
     * // => [1, 2, 3, [[4]]];
     *
     * // using `isDeep`
     * _.flatten([1, [2], [3, [[4]]]], true);
     * // => [1, 2, 3, 4];
     */
    function flatten(array, isDeep, guard) {
      var length = array ? array.length : 0;
      return length ? baseFlatten(array, guard ? false : isDeep) : [];
    }

    /**
     * Recursively flattens a nested array.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to recursively flatten.
     * @returns {Array} Returns the new flattened array.
     * @example
     *
     * _.flattenDeep([1, [2], [3, [[4]]]]);
     * // => [1, 2, 3, 4];
     */
    function flattenDeep(array) {
      var length = array ? array.length : 0;
      return length ? baseFlatten(array, true) : [];
    }

    /**
     * Gets the index at which the first occurrence of `value` is found in `array`
     * using `SameValueZero` for equality comparisons. If `fromIndex` is negative,
     * it is used as the offset from the end of the collection. If `array` is
     * sorted providing `true` for `fromIndex` performs a faster binary search.
     *
     * **Note:** `SameValueZero` is like strict equality, e.g. `===`, except that
     * `NaN` matches `NaN`. See the [ES6 spec](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * for more details.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to search.
     * @param {*} value The value to search for.
     * @param {boolean|number} [fromIndex=0] The index to search from or `true`
     *  to perform a binary search on a sorted array.
     * @returns {number} Returns the index of the matched value, else `-1`.
     * @example
     *
     * _.indexOf([1, 2, 3, 1, 2, 3], 2);
     * // => 1
     *
     * // using `fromIndex`
     * _.indexOf([1, 2, 3, 1, 2, 3], 2, 3);
     * // => 4
     *
     * // performing a binary search
     * _.indexOf([4, 4, 5, 5, 6, 6], 5, true);
     * // => 2
     */
    function indexOf(array, value, fromIndex) {
      var length = array ? array.length : 0;
      if (!length) {
        return -1;
      }
      if (typeof fromIndex == 'number') {
        fromIndex = fromIndex < 0 ? nativeMax(length + fromIndex, 0) : (fromIndex || 0);
      } else if (fromIndex) {
        var index = sortedIndex(array, value);
        return array[index] === value ? index : -1;
      }
      return baseIndexOf(array, value, fromIndex);
    }

    /**
     * Gets all but the last element of `array`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.initial([1, 2, 3]);
     * // => [1, 2]
     */
    function initial(array) {
      var length = array ? array.length : 0;
      return slice(array, 0, (length || 1) - 1);
    }

    /**
     * Creates an array of unique values present in all provided arrays using
     * `SameValueZero` for equality comparisons.
     *
     * **Note:** `SameValueZero` is like strict equality, e.g. `===`, except that
     * `NaN` matches `NaN`. See the [ES6 spec](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * for more details.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {...Array} [arrays] The arrays to inspect.
     * @returns {Array} Returns the new array of shared values.
     * @example
     *
     * _.intersection([1, 2, 3], [5, 2, 1, 4], [2, 1]);
     * // => [1, 2]
     */
    function intersection() {
      var args = [],
          argsIndex = -1,
          argsLength = arguments.length,
          caches = [],
          indexOf = getIndexOf(),
          prereq = createCache && indexOf == baseIndexOf;

      while (++argsIndex < argsLength) {
        var value = arguments[argsIndex];
        if (isArray(value) || isArguments(value)) {
          args.push(value);
          caches.push(prereq && value.length >= 120 &&
            createCache(argsIndex && value));
        }
      }
      argsLength = args.length;
      var array = args[0],
          index = -1,
          length = array ? array.length : 0,
          result = [],
          seen = caches[0];

      outer:
      while (++index < length) {
        value = array[index];
        if ((seen ? cacheIndexOf(seen, value) : indexOf(result, value)) < 0) {
          argsIndex = argsLength;
          while (--argsIndex) {
            var cache = caches[argsIndex];
            if ((cache ? cacheIndexOf(cache, value) : indexOf(args[argsIndex], value)) < 0) {
              continue outer;
            }
          }
          if (seen) {
            seen.push(value);
          }
          result.push(value);
        }
      }
      return result;
    }

    /**
     * Gets the last element of `array`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to query.
     * @returns {*} Returns the last element of `array`.
     * @example
     *
     * _.last([1, 2, 3]);
     * // => 3
     */
    function last(array) {
      var length = array ? array.length : 0;
      return length ? array[length - 1] : undefined;
    }

    /**
     * This method is like `_.indexOf` except that it iterates over elements of
     * `array` from right to left.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to search.
     * @param {*} value The value to search for.
     * @param {boolean|number} [fromIndex=array.length-1] The index to search from
     *  or `true` to perform a binary search on a sorted array.
     * @returns {number} Returns the index of the matched value, else `-1`.
     * @example
     *
     * _.lastIndexOf([1, 2, 3, 1, 2, 3], 2);
     * // => 4
     *
     * // using `fromIndex`
     * _.lastIndexOf([1, 2, 3, 1, 2, 3], 2, 3);
     * // => 1
     *
     * // performing a binary search
     * _.lastIndexOf([4, 4, 5, 5, 6, 6], 5, true);
     * // => 3
     */
    function lastIndexOf(array, value, fromIndex) {
      var length = array ? array.length : 0;
      if (!length) {
        return -1;
      }
      var index = length;
      if (typeof fromIndex == 'number') {
        index = (fromIndex < 0 ? nativeMax(length + fromIndex, 0) : nativeMin(fromIndex || 0, length - 1)) + 1;
      } else if (fromIndex) {
        index = sortedLastIndex(array, value) - 1;
        return array[index] === value ? index : -1;
      }
      if (value !== value) {
        return indexOfNaN(array, index, true);
      }
      while (index--) {
        if (array[index] === value) {
          return index;
        }
      }
      return -1;
    }

    /**
     * Removes all provided values from `array` using `SameValueZero` for equality
     * comparisons.
     *
     * **Notes:**
     *  - Unlike `_.without`, this method mutates `array`.
     *  - `SameValueZero` is like strict equality, e.g. `===`, except that `NaN` matches `NaN`.
     *    See the [ES6 spec](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     *    for more details.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to modify.
     * @param {...*} [values] The values to remove.
     * @returns {Array} Returns `array`.
     * @example
     *
     * var array = [1, 2, 3, 1, 2, 3];
     * _.pull(array, 2, 3);
     * console.log(array);
     * // => [1, 1]
     */
    function pull() {
      var array = arguments[0];
      if (!(array && array.length)) {
        return array;
      }
      var index = 0,
          indexOf = getIndexOf(),
          length = arguments.length;

      while (++index < length) {
        var fromIndex = 0,
            value = arguments[index];

        while ((fromIndex = indexOf(array, value, fromIndex)) > -1) {
          splice.call(array, fromIndex, 1);
        }
      }
      return array;
    }

    /**
     * Removes elements from `array` corresponding to the specified indexes and
     * returns an array of the removed elements. Indexes may be specified as an
     * array of indexes or as individual arguments.
     *
     * **Note:** Unlike `_.at`, this method mutates `array`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to modify.
     * @param {...(number|number[])} [indexes] The indexes of elements to remove,
     *  specified as individual indexes or arrays of indexes.
     * @returns {Array} Returns the new array of removed elements.
     * @example
     *
     * var array = [5, 10, 15, 20];
     * var evens = _.pullAt(array, [1, 3]);
     *
     * console.log(array);
     * // => [5, 15]
     *
     * console.log(evens);
     * // => [10, 20]
     */
    function pullAt(array) {
      return basePullAt(array, baseFlatten(arguments, false, false, 1));
    }

    /**
     * Removes all elements from `array` that `predicate` returns truthy for
     * and returns an array of the removed elements. The predicate is bound to
     * `thisArg` and invoked with three arguments; (value, index, array).
     *
     * If a property name is provided for `predicate` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `predicate` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * **Note:** Unlike `_.filter`, this method mutates `array`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to modify.
     * @param {Function|Object|string} [predicate=identity] The function invoked
     *  per iteration. If a property name or object is provided it is used to
     *  create a "_.pluck" or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the new array of removed elements.
     * @example
     *
     * var array = [1, 2, 3, 4];
     * var evens = _.remove(array, function(n) { return n % 2 == 0; });
     *
     * console.log(array);
     * // => [1, 3]
     *
     * console.log(evens);
     * // => [2, 4]
     */
    function remove(array, predicate, thisArg) {
      var index = -1,
          length = array ? array.length : 0,
          result = [];

      predicate = getCallback(predicate, thisArg, 3);
      while (++index < length) {
        var value = array[index];
        if (predicate(value, index, array)) {
          result.push(value);
          splice.call(array, index--, 1);
          length--;
        }
      }
      return result;
    }

    /**
     * Gets all but the first element of `array`.
     *
     * @static
     * @memberOf _
     * @alias tail
     * @category Array
     * @param {Array} array The array to query.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.rest([1, 2, 3]);
     * // => [2, 3]
     */
    function rest(array) {
      return slice(array, 1);
    }

    /**
     * Slices `array` from the `start` index up to, but not including, the `end` index.
     *
     * **Note:** This function is used instead of `Array#slice` to support node lists
     * in IE < 9 and to ensure dense arrays are returned.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to slice.
     * @param {number} [start=0] The start index.
     * @param {number} [end=array.length] The end index.
     * @returns {Array} Returns the slice of `array`.
     */
    function slice(array, start, end) {
      var index = -1,
          length = array ? array.length : 0,
          endType = typeof end;

      if (end && endType != 'number' && isIterateeCall(array, start, end)) {
        start = 0;
        end = length;
      }
      start = start == null ? 0 : (+start || 0);
      if (start < 0) {
        start = -start > length ? 0 : (length + start);
      }
      end = (endType == 'undefined' || end > length) ? length : (+end || 0);
      if (end < 0) {
        end += length;
      }
      if (end && end == length && !start) {
        return baseSlice(array);
      }
      length = start > end ? 0 : (end - start);

      var result = Array(length);
      while (++index < length) {
        result[index] = array[index + start];
      }
      return result;
    }

    /**
     * Uses a binary search to determine the lowest index at which a value should
     * be inserted into a given sorted array in order to maintain the sort order
     * of the array. If an iteratee function is provided it is invoked for `value`
     * and each element of `array` to compute their sort ranking. The iteratee
     * is bound to `thisArg` and invoked with one argument; (value).
     *
     * If a property name is provided for `iteratee` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `iteratee` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to inspect.
     * @param {*} value The value to evaluate.
     * @param {Function|Object|string} [iteratee=identity] The function invoked
     *  per iteration. If a property name or object is provided it is used to
     *  create a "_.pluck" or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {number} Returns the index at which `value` should be inserted
     *  into `array`.
     * @example
     *
     * _.sortedIndex([30, 50], 40);
     * // => 1
     *
     * _.sortedIndex([4, 4, 5, 5, 6, 6], 5);
     * // => 2
     *
     * var dict = { 'data': { 'thirty': 30, 'forty': 40, 'fifty': 50 } };
     *
     * // using an iteratee function
     * _.sortedIndex(['thirty', 'fifty'], 'forty', function(word) {
     *   return this.data[word];
     * }, dict);
     * // => 1
     *
     * // using "_.pluck" callback shorthand
     * _.sortedIndex([{ 'x': 30 }, { 'x': 50 }], { 'x': 40 }, 'x');
     * // => 1
     */
    function sortedIndex(array, value, iteratee, thisArg) {
      iteratee = iteratee == null ? identity : getCallback(iteratee, thisArg, 1);
      return baseSortedIndex(array, value, iteratee);
    }

    /**
     * This method is like `_.sortedIndex` except that it returns the highest
     * index at which a value should be inserted into a given sorted array in
     * order to maintain the sort order of the array.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to inspect.
     * @param {*} value The value to evaluate.
     * @param {Function|Object|string} [iteratee=identity] The function invoked
     *  per iteration. If a property name or object is provided it is used to
     *  create a "_.pluck" or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {number} Returns the index at which `value` should be inserted
     *  into `array`.
     * @example
     *
     * _.sortedLastIndex([4, 4, 5, 5, 6, 6], 5);
     * // => 4
     */
    function sortedLastIndex(array, value, iteratee, thisArg) {
      iteratee = iteratee == null ? identity : getCallback(iteratee, thisArg, 1);
      return baseSortedIndex(array, value, iteratee, true);
    }

    /**
     * Creates a slice of `array` with `n` elements taken from the beginning.
     *
     * @static
     * @memberOf _
     * @type Function
     * @category Array
     * @param {Array} array The array to query.
     * @param {number} [n=1] The number of elements to take.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.take([1, 2, 3], 1);
     * // => [1]
     *
     * _.take([1, 2, 3], 2);
     * // => [1, 2]
     *
     * _.take([1, 2, 3], 5);
     * // => [1, 2, 3]
     *
     * _.take([1, 2, 3], 0);
     * // => []
     */
    function take(array, n, guard) {
      n = (guard || n == null) ? 1 : n;
      return slice(array, 0, n < 0 ? 0 : n);
    }

    /**
     * Creates a slice of `array` with `n` elements taken from the end.
     *
     * @static
     * @memberOf _
     * @type Function
     * @category Array
     * @param {Array} array The array to query.
     * @param {number} [n=1] The number of elements to take.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.takeRight([1, 2, 3], 1);
     * // => [3]
     *
     * _.takeRight([1, 2, 3], 2);
     * // => [2, 3]
     *
     * _.takeRight([1, 2, 3], 5);
     * // => [1, 2, 3]
     *
     * _.takeRight([1, 2, 3], 0);
     * // => []
     */
    function takeRight(array, n, guard) {
      var length = array ? array.length : 0;
      n = (guard || n == null) ? 1 : n;
      n = length - (n || 0);
      return slice(array, n < 0 ? 0 : n);
    }

    /**
     * Creates a slice of `array` with elements taken from the end. Elements are
     * taken until `predicate` returns falsey. The predicate is bound to `thisArg`
     * and invoked with three arguments; (value, index, array).
     *
     * If a property name is provided for `predicate` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `predicate` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @type Function
     * @category Array
     * @param {Array} array The array to query.
     * @param {Function|Object|string} [predicate=identity] The function invoked
     *  per element.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.takeRightWhile([1, 2, 3], function(n) { return n > 1; });
     * // => [2, 3]
     *
     * var users = [
     *   { 'user': 'barney',  'employer': 'slate' },
     *   { 'user': 'fred',    'employer': 'slate', 'blocked': true },
     *   { 'user': 'pebbles', 'employer': 'na',    'blocked': true }
     * ];
     *
     * // using "_.pluck" callback shorthand
     * _.pluck(_.takeRightWhile(users, 'blocked'), 'user');
     * // => ['fred', 'pebbles']
     *
     * // using "_.where" callback shorthand
     * _.pluck(_.takeRightWhile(users, { 'employer': 'na' }), 'user');
     * // => ['pebbles']
     */
    function takeRightWhile(array, predicate, thisArg) {
      var length = array ? array.length : 0,
          index = length;

      predicate = getCallback(predicate, thisArg, 3);
      while (index-- && predicate(array[index], index, array)) {}
      return slice(array, index + 1);
    }

    /**
     * Creates a slice of `array` with elements taken from the beginning. Elements
     * are taken until `predicate` returns falsey. The predicate is bound to
     * `thisArg` and invoked with three arguments; (value, index, array).
     *
     * If a property name is provided for `predicate` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `predicate` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @type Function
     * @category Array
     * @param {Array} array The array to query.
     * @param {Function|Object|string} [predicate=identity] The function invoked
     *  per element.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the slice of `array`.
     * @example
     *
     * _.takeWhile([1, 2, 3], function(n) { return n < 3; });
     * // => [1, 2]
     *
     * var users = [
     *   { 'user': 'barney',  'employer': 'slate', 'blocked': true },
     *   { 'user': 'fred',    'employer': 'slate' },
     *   { 'user': 'pebbles', 'employer': 'na',    'blocked': true }
     * ];
     *
     * // using "_.pluck" callback shorthand
     * _.pluck(_.takeWhile(users, 'blocked'), 'user');
     * // => ['barney']
     *
     * // using "_.where" callback shorthand
     * _.pluck(_.takeWhile(users, { 'employer': 'slate' }), 'user');
     * // => ['barney', 'fred']
     */
    function takeWhile(array, predicate, thisArg) {
      var index = -1,
          length = array ? array.length : 0;

      predicate = getCallback(predicate, thisArg, 3);
      while (++index < length && predicate(array[index], index, array)) {}
      return slice(array, 0, index);
    }

    /**
     * Creates an array of unique values, in order, of the provided arrays using
     * `SameValueZero` for equality comparisons.
     *
     * **Note:** `SameValueZero` is like strict equality, e.g. `===`, except that
     * `NaN` matches `NaN`. See the [ES6 spec](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * for more details.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {...Array} [arrays] The arrays to inspect.
     * @returns {Array} Returns the new array of combined values.
     * @example
     *
     * _.union([1, 2, 3], [5, 2, 1, 4], [2, 1]);
     * // => [1, 2, 3, 5, 4]
     */
    function union() {
      return baseUniq(baseFlatten(arguments, false, true));
    }

    /**
     * Creates a duplicate-value-free version of an array using `SameValueZero`
     * for equality comparisons. Providing `true` for `isSorted` performs a faster
     * search algorithm for sorted arrays. If an iteratee function is provided it
     * is invoked for each value in the array to generate the criterion by which
     * uniqueness is computed. The `iteratee` is bound to `thisArg` and invoked
     * with three arguments; (value, index, array).
     *
     * If a property name is provided for `iteratee` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `iteratee` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * **Note:** `SameValueZero` is like strict equality, e.g. `===`, except that
     * `NaN` matches `NaN`. See the [ES6 spec](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * for more details.
     *
     * @static
     * @memberOf _
     * @alias unique
     * @category Array
     * @param {Array} array The array to inspect.
     * @param {boolean} [isSorted=false] Specify the array is sorted.
     * @param {Function|Object|string} [iteratee] The function invoked per iteration.
     *  If a property name or object is provided it is used to create a "_.pluck"
     *  or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Array} Returns the new duplicate-value-free array.
     * @example
     *
     * _.uniq([1, 2, 1]);
     * // => [1, 2]
     *
     * // using `isSorted`
     * _.uniq([1, 1, 2], true);
     * // => [1, 2]
     *
     * // using an iteratee function
     * _.uniq([1, 2.5, 1.5, 2], function(n) { return this.floor(n); }, Math);
     * // => [1, 2.5]
     *
     * // using "_.pluck" callback shorthand
     * _.uniq([{ 'x': 1 }, { 'x': 2 }, { 'x': 1 }], 'x');
     * // => [{ 'x': 1 }, { 'x': 2 }]
     */
    function uniq(array, isSorted, iteratee, thisArg) {
      var length = array ? array.length : 0;
      if (!length) {
        return [];
      }
      // juggle arguments
      if (typeof isSorted != 'boolean' && isSorted != null) {
        thisArg = iteratee;
        iteratee = isIterateeCall(array, isSorted, thisArg) ? null : isSorted;
        isSorted = false;
      }
      if (iteratee != null) {
        iteratee = getCallback(iteratee, thisArg, 3);
      }
      return (isSorted && getIndexOf() == baseIndexOf)
        ? sortedUniq(array, iteratee)
        : baseUniq(array, iteratee);
    }

    /**
     * This method is like `_.zip` except that it accepts an array of grouped
     * elements and creates an array regrouping the elements to their pre `_.zip`
     * configuration.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array of grouped elements to process.
     * @returns {Array} Returns the new array of regrouped elements.
     * @example
     *
     * var zipped = _.zip(['fred', 'barney'], [30, 40], [true, false]);
     * // => [['fred', 30, true], ['barney', 40, false]]
     *
     * _.unzip(zipped);
     * // => [['fred', 'barney'], [30, 40], [true, false]]
     */
    function unzip(array) {
      var index = -1,
          length = isObject(length = max(array, 'length')) && length.length || 0,
          result = Array(length);

      while (++index < length) {
        result[index] = pluck(array, index);
      }
      return result;
    }

    /**
     * Creates an array excluding all provided values using `SameValueZero` for
     * equality comparisons.
     *
     * **Note:** `SameValueZero` is like strict equality, e.g. `===`, except that
     * `NaN` matches `NaN`. See the [ES6 spec](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * for more details.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {Array} array The array to filter.
     * @param {...*} [values] The values to exclude.
     * @returns {Array} Returns the new array of filtered values.
     * @example
     *
     * _.without([1, 2, 1, 0, 3, 1, 4], 0, 1);
     * // => [2, 3, 4]
     */
    function without(array) {
      return baseDifference(array, slice(arguments, 1));
    }

    /**
     * Creates an array that is the symmetric difference of the provided arrays.
     * See [Wikipedia](http://en.wikipedia.org/wiki/Symmetric_difference) for
     * more details.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {...Array} [arrays] The arrays to inspect.
     * @returns {Array} Returns the new array of values.
     * @example
     *
     * _.xor([1, 2, 3], [5, 2, 1, 4]);
     * // => [3, 5, 4]
     *
     * _.xor([1, 2, 5], [2, 3, 5], [3, 4, 5]);
     * // => [1, 4, 5]
     */
    function xor() {
      var index = -1,
          length = arguments.length;

      while (++index < length) {
        var array = arguments[index];
        if (isArray(array) || isArguments(array)) {
          var result = result
            ? baseDifference(result, array).concat(baseDifference(array, result))
            : array;
        }
      }
      return result ? baseUniq(result) : [];
    }

    /**
     * Creates an array of grouped elements, the first of which contains the first
     * elements of the given arrays, the second of which contains the second elements
     * of the given arrays, and so on.
     *
     * @static
     * @memberOf _
     * @category Array
     * @param {...Array} [arrays] The arrays to process.
     * @returns {Array} Returns the new array of grouped elements.
     * @example
     *
     * _.zip(['fred', 'barney'], [30, 40], [true, false]);
     * // => [['fred', 30, true], ['barney', 40, false]]
     */
    function zip() {
      var length = arguments.length,
          array = Array(length);

      while (length--) {
        array[length] = arguments[length];
      }
      return unzip(array);
    }

    /**
     * Creates an object composed from arrays of property names and values. Provide
     * either a single two dimensional array, e.g. `[[key1, value1], [key2, value2]]`
     * or two arrays, one of property names and one of corresponding values.
     *
     * @static
     * @memberOf _
     * @alias object
     * @category Array
     * @param {Array} props The property names.
     * @param {Array} [vals=[]] The property values.
     * @returns {Object} Returns the new object.
     * @example
     *
     * _.zipObject(['fred', 'barney'], [30, 40]);
     * // => { 'fred': 30, 'barney': 40 }
     */
    function zipObject(props, vals) {
      var index = -1,
          length = props ? props.length : 0,
          result = {};

      if (!vals && length && !isArray(props[0])) {
        vals = [];
      }
      while (++index < length) {
        var key = props[index];
        if (vals) {
          result[key] = vals[index];
        } else if (key) {
          result[key[0]] = key[1];
        }
      }
      return result;
    }

    /*------------------------------------------------------------------------*/

    /**
     * Creates a `lodash` object that wraps `value` with explicit method
     * chaining enabled.
     *
     * @static
     * @memberOf _
     * @category Chain
     * @param {*} value The value to wrap.
     * @returns {Object} Returns the new wrapper object.
     * @example
     *
     * var users = [
     *   { 'user': 'barney',  'age': 36 },
     *   { 'user': 'fred',    'age': 40 },
     *   { 'user': 'pebbles', 'age': 1 }
     * ];
     *
     * var youngest = _.chain(users)
     *     .sortBy('age')
     *     .map(function(chr) { return chr.user + ' is ' + chr.age; })
     *     .first()
     *     .value();
     * // => 'pebbles is 1'
     */
    function chain(value) {
      var result = lodash(value);
      result.__chain__ = true;
      return result;
    }

    /**
     * This method invokes `interceptor` and returns `value`. The interceptor is
     * bound to `thisArg` and invoked with one argument; (value). The purpose of
     * this method is to "tap into" a method chain in order to perform operations
     * on intermediate results within the chain.
     *
     * @static
     * @memberOf _
     * @category Chain
     * @param {*} value The value to provide to `interceptor`.
     * @param {Function} interceptor The function to invoke.
     * @param {*} [thisArg] The `this` binding of `interceptor`.
     * @returns {*} Returns `value`.
     * @example
     *
     * _([1, 2, 3])
     *  .tap(function(array) { array.pop(); })
     *  .reverse()
     *  .value();
     * // => [2, 1]
     */
    function tap(value, interceptor, thisArg) {
      interceptor.call(thisArg, value);
      return value;
    }

    /**
     * This method is like `_.tap` except that it returns the result of `interceptor`.
     *
     * @static
     * @memberOf _
     * @category Chain
     * @param {*} value The value to provide to `interceptor`.
     * @param {Function} interceptor The function to invoke.
     * @param {*} [thisArg] The `this` binding of `interceptor`.
     * @returns {*} Returns the result of `interceptor`.
     * @example
     *
     * _([1, 2, 3])
     *  .last()
     *  .thru(function(value) { return [value]; })
     *  .value();
     * // => [3]
     */
    function thru(value, interceptor, thisArg) {
      return interceptor.call(thisArg, value);
    }

    /**
     * Enables explicit method chaining on the wrapper object.
     *
     * @name chain
     * @memberOf _
     * @category Chain
     * @returns {*} Returns the wrapper object.
     * @example
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40 }
     * ];
     *
     * // without explicit chaining
     * _(users).first();
     * // => { 'user': 'barney', 'age': 36 }
     *
     * // with explicit chaining
     * _(users).chain()
     *   .first()
     *   .pick('age')
     *   .value();
     * // => { 'age': 36 }
     */
    function wrapperChain() {
      return chain(this);
    }

    /**
     * Produces the result of coercing the unwrapped value to a string.
     *
     * @name toString
     * @memberOf _
     * @category Chain
     * @returns {string} Returns the coerced string value.
     * @example
     *
     * _([1, 2, 3]).toString();
     * // => '1,2,3'
     */
    function wrapperToString() {
      return String(this.value());
    }

    /**
     * Extracts the unwrapped value from its wrapper.
     *
     * @name valueOf
     * @memberOf _
     * @alias toJSON, value
     * @category Chain
     * @returns {*} Returns the unwrapped value.
     * @example
     *
     * _([1, 2, 3]).valueOf();
     * // => [1, 2, 3]
     */
    function wrapperValueOf() {
      var index = -1,
          queue = this.__queue__,
          length = queue.length,
          result = this.__wrapped__;

      while (++index < length) {
        var args = [result],
            data = queue[index],
            object = data[1];

        push.apply(args, data[2]);
        result = object[data[0]].apply(object, args);
      }
      return result;
    }

    /*------------------------------------------------------------------------*/

    /**
     * Creates an array of elements corresponding to the specified keys, or indexes,
     * of the collection. Keys may be specified as individual arguments or as arrays
     * of keys.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {...(number|number[]|string|string[])} [props] The property names
     *  or indexes of elements to pick, specified individually or in arrays.
     * @returns {Array} Returns the new array of picked elements.
     * @example
     *
     * _.at(['a', 'b', 'c', 'd', 'e'], [0, 2, 4]);
     * // => ['a', 'c', 'e']
     *
     * _.at(['fred', 'barney', 'pebbles'], 0, 2);
     * // => ['fred', 'pebbles']
     */
    function at(collection) {
      var length = collection ? collection.length : 0;

      if (typeof length == 'number' && length > -1 && length <= MAX_SAFE_INTEGER) {
        collection = toIterable(collection);
      }
      return baseAt(collection, baseFlatten(arguments, false, false, 1));
    }

    /**
     * Checks if `value` is present in `collection` using  `SameValueZero` for
     * equality comparisons. If `fromIndex` is negative, it is used as the offset
     * from the end of the collection.
     *
     * **Note:** `SameValueZero` is like strict equality, e.g. `===`, except that
     * `NaN` matches `NaN`. See the [ES6 spec](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
     * for more details.
     *
     * @static
     * @memberOf _
     * @alias include
     * @category Collection
     * @param {Array|Object|string} collection The collection to search.
     * @param {*} target The value to check for.
     * @param {number} [fromIndex=0] The index to search from.
     * @returns {boolean} Returns `true` if a matching element is found, else `false`.
     * @example
     *
     * _.contains([1, 2, 3], 1);
     * // => true
     *
     * _.contains([1, 2, 3], 1, 2);
     * // => false
     *
     * _.contains({ 'user': 'fred', 'age': 40 }, 'fred');
     * // => true
     *
     * _.contains('pebbles', 'eb');
     * // => true
     */
    function contains(collection, target, fromIndex) {
      var length = collection ? collection.length : 0;

      if (!(typeof length == 'number' && length > -1 && length <= MAX_SAFE_INTEGER)) {
        collection = values(collection);
        length = collection.length;
      }
      if (!length) {
        return false;
      }
      if (typeof fromIndex == 'number') {
        fromIndex = fromIndex < 0 ? nativeMax(length + fromIndex, 0) : (fromIndex || 0);
      } else {
        fromIndex = 0;
      }
      return (typeof collection == 'string' || !isArray(collection) && isString(collection))
        ? (fromIndex < length && collection.indexOf(target, fromIndex) > -1)
        : (getIndexOf(collection, target, fromIndex) > -1);
    }

    /**
     * Creates an object composed of keys generated from the results of running
     * each element of `collection` through `iteratee`. The corresponding value
     * of each key is the number of times the key was returned by `iteratee`.
     * The `iteratee` is bound to `thisArg` and invoked with three arguments;
     * (value, index|key, collection).
     *
     * If a property name is provided for `iteratee` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `iteratee` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee=identity] The function invoked
     *  per iteration. If a property name or object is provided it is used to
     *  create a "_.pluck" or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns the composed aggregate object.
     * @example
     *
     * _.countBy([4.3, 6.1, 6.4], function(n) { return Math.floor(n); });
     * // => { '4': 1, '6': 2 }
     *
     * _.countBy([4.3, 6.1, 6.4], function(n) { return this.floor(n); }, Math);
     * // => { '4': 1, '6': 2 }
     *
     * _.countBy(['one', 'two', 'three'], 'length');
     * // => { '3': 2, '5': 1 }
     */
    var countBy = createAggregator(function(result, value, key) {
      hasOwnProperty.call(result, key) ? ++result[key] : (result[key] = 1);
    });

    /**
     * Checks if `predicate` returns truthy for **all** elements of `collection`.
     * The predicate is bound to `thisArg` and invoked with three arguments;
     * (value, index|key, collection).
     *
     * If a property name is provided for `predicate` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `predicate` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @alias all
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [predicate=identity] The function invoked
     *  per iteration. If a property name or object is provided it is used to
     *  create a "_.pluck" or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {boolean} Returns `true` if all elements pass the predicate check,
     *  else `false`.
     * @example
     *
     * _.every([true, 1, null, 'yes']);
     * // => false
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40 }
     * ];
     *
     * // using "_.pluck" callback shorthand
     * _.every(users, 'age');
     * // => true
     *
     * // using "_.where" callback shorthand
     * _.every(users, { 'age': 36 });
     * // => false
     */
    function every(collection, predicate, thisArg) {
      var func = isArray(collection) ? arrayEvery : baseEvery;
      if (typeof predicate != 'function' || typeof thisArg != 'undefined') {
        predicate = getCallback(predicate, thisArg, 3);
      }
      return func(collection, predicate);
    }

    /**
     * Iterates over elements of `collection`, returning an array of all elements
     * `predicate` returns truthy for. The predicate is bound to `thisArg` and
     * invoked with three arguments; (value, index|key, collection).
     *
     * If a property name is provided for `predicate` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `predicate` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @alias select
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [predicate=identity] The function invoked
     *  per iteration. If a property name or object is provided it is used to
     *  create a "_.pluck" or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the new filtered array.
     * @example
     *
     * var evens = _.filter([1, 2, 3, 4], function(n) { return n % 2 == 0; });
     * // => [2, 4]
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40, 'blocked': true }
     * ];
     *
     * // using "_.pluck" callback shorthand
     * _.filter(users, 'blocked');
     * // => [{ 'user': 'fred', 'age': 40, 'blocked': true }]
     *
     * // using "_.where" callback shorthand
     * _.filter(users, { 'age': 36 });
     * // => [{ 'user': 'barney', 'age': 36 }]
     */
    function filter(collection, predicate, thisArg) {
      var func = isArray(collection) ? arrayFilter : baseFilter;

      predicate = getCallback(predicate, thisArg, 3);
      return func(collection, predicate);
    }

    /**
     * Iterates over elements of `collection`, returning the first element
     * `predicate` returns truthy for. The predicate is bound to `thisArg` and
     * invoked with three arguments; (value, index|key, collection).
     *
     * If a property name is provided for `predicate` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `predicate` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @alias detect
     * @category Collection
     * @param {Array|Object|string} collection The collection to search.
     * @param {Function|Object|string} [predicate=identity] The function invoked
     *  per iteration. If a property name or object is provided it is used to
     *  create a "_.pluck" or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {*} Returns the matched element, else `undefined`.
     * @example
     *
     * var users = [
     *   { 'user': 'barney',  'age': 36 },
     *   { 'user': 'fred',    'age': 40, 'blocked': true },
     *   { 'user': 'pebbles', 'age': 1 }
     * ];
     *
     * _.find(users, function(chr) {
     *   return chr.age < 40;
     * });
     * // => { 'user': 'barney', 'age': 36 }
     *
     * // using "_.where" callback shorthand
     * _.find(users, { 'age': 1 });
     * // =>  { 'user': 'pebbles', 'age': 1 }
     *
     * // using "_.pluck" callback shorthand
     * _.find(users, 'blocked');
     * // => { 'user': 'fred', 'age': 40, 'blocked': true }
     */
    function find(collection, predicate, thisArg) {
      if (isArray(collection)) {
        var index = findIndex(collection, predicate, thisArg);
        return index > -1 ? collection[index] : undefined;
      }
      predicate = getCallback(predicate, thisArg, 3);
      return baseFind(collection, predicate, baseEach);
    }

    /**
     * This method is like `_.find` except that it iterates over elements of
     * `collection` from right to left.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to search.
     * @param {Function|Object|string} [predicate=identity] The function invoked
     *  per iteration. If a property name or object is provided it is used to
     *  create a "_.pluck" or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {*} Returns the matched element, else `undefined`.
     * @example
     *
     * _.findLast([1, 2, 3, 4], function(n) { return n % 2 == 1; });
     * // => 3
     */
    function findLast(collection, predicate, thisArg) {
      predicate = getCallback(predicate, thisArg, 3);
      return baseFind(collection, predicate, baseEachRight);
    }

    /**
     * Performs a deep comparison between each element in `collection` and the
     * source object, returning the first element that has equivalent property
     * values.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to search.
     * @param {Object} source The object of property values to match.
     * @returns {*} Returns the matched element, else `undefined`.
     * @example
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36, 'employer': 'slate' },
     *   { 'user': 'fred',   'age': 40, 'employer': 'slate' }
     * ];
     *
     * _.findWhere(users, { 'employer': 'slate' });
     * // => { 'user': 'barney', 'age': 36, 'employer': 'slate' }
     *
     * _.findWhere(users, { 'age': 40 });
     * // =>  { 'user': 'fred', 'age': 40, 'employer': 'slate' }
     */
    function findWhere(collection, source) {
      return find(collection, matches(source));
    }

    /**
     * Iterates over elements of `collection` invoking `iteratee` for each element.
     * The `iteratee` is bound to `thisArg` and invoked with three arguments;
     * (value, index|key, collection). Iterator functions may exit iteration early
     * by explicitly returning `false`.
     *
     * **Note:** As with other "Collections" methods, objects with a `length` property
     * are iterated like arrays. To avoid this behavior `_.forIn` or `_.forOwn`
     * may be used for object iteration.
     *
     * @static
     * @memberOf _
     * @alias each
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} [iteratee=identity] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Array|Object|string} Returns `collection`.
     * @example
     *
     * _([1, 2, 3]).forEach(function(n) { console.log(n); });
     * // => logs each value from left to right and returns the array
     *
     * _.forEach({ 'one': 1, 'two': 2, 'three': 3 }, function(n, key) { console.log(n, key); });
     * // => logs each value-key pair and returns the object (iteration order is not guaranteed)
     */
    function forEach(collection, iteratee, thisArg) {
      return (typeof iteratee == 'function' && typeof thisArg == 'undefined' && isArray(collection))
        ? arrayEach(collection, iteratee)
        : baseEach(collection, baseCallback(iteratee, thisArg, 3));
    }

    /**
     * This method is like `_.forEach` except that it iterates over elements of
     * `collection` from right to left.
     *
     * @static
     * @memberOf _
     * @alias eachRight
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} [iteratee=identity] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Array|Object|string} Returns `collection`.
     * @example
     *
     * _([1, 2, 3]).forEachRight(function(n) { console.log(n); }).join(',');
     * // => logs each value from right to left and returns the array
     */
    function forEachRight(collection, iteratee, thisArg) {
      return (typeof iteratee == 'function' && typeof thisArg == 'undefined' && isArray(collection))
        ? arrayEachRight(collection, iteratee)
        : baseEachRight(collection, baseCallback(iteratee, thisArg, 3));
    }

    /**
     * Creates an object composed of keys generated from the results of running
     * each element of `collection` through `iteratee`. The corresponding
     * value of each key is an array of the elements responsible for generating
     * the key. The `iteratee` is bound to `thisArg` and invoked with three
     * arguments; (value, index|key, collection).
     *
     * If a property name is provided for `iteratee` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `iteratee` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee=identity] The function invoked
     *  per iteration. If a property name or object is provided it is used to
     *  create a "_.pluck" or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns the composed aggregate object.
     * @example
     *
     * _.groupBy([4.2, 6.1, 6.4], function(n) { return Math.floor(n); });
     * // => { '4': [4.2], '6': [6.1, 6.4] }
     *
     * _.groupBy([4.2, 6.1, 6.4], function(n) { return this.floor(n); }, Math);
     * // => { '4': [4.2], '6': [6.1, 6.4] }
     *
     * // using "_.pluck" callback shorthand
     * _.groupBy(['one', 'two', 'three'], 'length');
     * // => { '3': ['one', 'two'], '5': ['three'] }
     */
    var groupBy = createAggregator(function(result, value, key) {
      if (hasOwnProperty.call(result, key)) {
        result[key].push(value);
      } else {
        result[key] = [value];
      }
    });

    /**
     * Creates an object composed of keys generated from the results of running
     * each element of the collection through `iteratee`. The corresponding value
     * of each key is the last element responsible for generating the key. The
     * iteratee function is bound to `thisArg` and invoked with three arguments;
     * (value, index|key, collection).
     *
     * If a property name is provided for `iteratee` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `iteratee` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee=identity] The function invoked
     *  per iteration. If a property name or object is provided it is used to
     *  create a "_.pluck" or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns the composed aggregate object.
     * @example
     *
     * var keyData = [
     *   { 'dir': 'left', 'code': 97 },
     *   { 'dir': 'right', 'code': 100 }
     * ];
     *
     * _.indexBy(keyData, 'dir');
     * // => { 'left': { 'dir': 'left', 'code': 97 }, 'right': { 'dir': 'right', 'code': 100 } }
     *
     * _.indexBy(keyData, function(object) { return String.fromCharCode(object.code); });
     * // => { 'a': { 'dir': 'left', 'code': 97 }, 'd': { 'dir': 'right', 'code': 100 } }
     *
     * _.indexBy(keyData, function(object) { return this.fromCharCode(object.code); }, String);
     * // => { 'a': { 'dir': 'left', 'code': 97 }, 'd': { 'dir': 'right', 'code': 100 } }
     */
    var indexBy = createAggregator(function(result, value, key) {
      result[key] = value;
    });

    /**
     * Invokes the method named by `methodName` on each element in the collection,
     * returning an array of the results of each invoked method. Any additional
     * arguments are provided to each invoked method. If `methodName` is a function
     * it is invoked for, and `this` bound to, each element in the collection.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|string} methodName The name of the method to invoke or
     *  the function invoked per iteration.
     * @param {...*} [args] The arguments to invoke the method with.
     * @returns {Array} Returns the array of results.
     * @example
     *
     * _.invoke([[5, 1, 7], [3, 2, 1]], 'sort');
     * // => [[1, 5, 7], [1, 2, 3]]
     *
     * _.invoke([123, 456], String.prototype.split, '');
     * // => [['1', '2', '3'], ['4', '5', '6']]
     */
    function invoke(collection, methodName) {
      return baseInvoke(collection, methodName, slice(arguments, 2));
    }

    /**
     * Creates an array of values by running each element in the collection through
     * `iteratee`. The `iteratee` is bound to `thisArg` and invoked with three
     * arguments; (value, index|key, collection).
     *
     * If a property name is provided for `iteratee` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `iteratee` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @alias collect
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee=identity] The function invoked
     *  per iteration. If a property name or object is provided it is used to
     *  create a "_.pluck" or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Array} Returns the new mapped array.
     * @example
     *
     * _.map([1, 2, 3], function(n) { return n * 3; });
     * // => [3, 6, 9]
     *
     * _.map({ 'one': 1, 'two': 2, 'three': 3 }, function(n) { return n * 3; });
     * // => [3, 6, 9] (iteration order is not guaranteed)
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40 }
     * ];
     *
     * // using "_.pluck" callback shorthand
     * _.map(users, 'user');
     * // => ['barney', 'fred']
     */
    function map(collection, iteratee, thisArg) {
      iteratee = getCallback(iteratee, thisArg, 3);

      var func = isArray(collection) ? arrayMap : baseMap;
      return func(collection, iteratee);
    }

    /**
     * Retrieves the maximum value of `collection`. If the collection is empty
     * or falsey `-Infinity` is returned. If an iteratee function is provided it
     * is invoked for each value in the collection to generate the criterion by
     * which the value is ranked. The `iteratee` is bound to `thisArg` and invoked
     * with three arguments; (value, index, collection).
     *
     * If a property name is provided for `iteratee` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `iteratee` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee] The function invoked per iteration.
     *  If a property name or object is provided it is used to create a "_.pluck"
     *  or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {*} Returns the maximum value.
     * @example
     *
     * _.max([4, 2, 8, 6]);
     * // => 8
     *
     * _.max([]);
     * // => -Infinity
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40 }
     * ];
     *
     * _.max(users, function(chr) { return chr.age; });
     * // => { 'user': 'fred', 'age': 40 };
     *
     * // using "_.pluck" callback shorthand
     * _.max(users, 'age');
     * // => { 'user': 'fred', 'age': 40 };
     */
    function max(collection, iteratee, thisArg) {
      iteratee = isIterateeCall(collection, iteratee, thisArg) ? null : iteratee;

      var computed = -Infinity,
          noIteratee = iteratee == null,
          isArr = noIteratee && isArray(collection),
          isStr = !isArr && isString(collection),
          result = computed;

      if (noIteratee && !isStr) {
        var index = -1,
            iterable = toIterable(collection),
            length = iterable.length;

        while (++index < length) {
          var value = iterable[index];
          if (value > result) {
            result = value;
          }
        }
      } else {
        iteratee = (noIteratee && isStr)
          ? charAtCallback
          : getCallback(iteratee, thisArg, 3);

        baseEach(collection, function(value, index, collection) {
          var current = iteratee(value, index, collection);
          if (current > computed || (current === -Infinity && current === result)) {
            computed = current;
            result = value;
          }
        });
      }
      return result;
    }

    /**
     * Retrieves the minimum value of `collection`. If the collection is empty
     * or falsey `Infinity` is returned. If an iteratee function is provided it
     * is invoked for each value in the collection to generate the criterion by
     * which the value is ranked. The `iteratee` is bound to `thisArg` and invoked
     * with three arguments; (value, index, collection).
     *
     * If a property name is provided for `iteratee` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `iteratee` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [iteratee] The function invoked per iteration.
     *  If a property name or object is provided it is used to create a "_.pluck"
     *  or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {*} Returns the minimum value.
     * @example
     *
     * _.min([4, 2, 8, 6]);
     * // => 2
     *
     * _.min([]);
     * // => Infinity
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40 }
     * ];
     *
     * _.min(users, function(chr) { return chr.age; });
     * // => { 'user': 'barney', 'age': 36 };
     *
     * // using "_.pluck" callback shorthand
     * _.min(users, 'age');
     * // => { 'user': 'barney', 'age': 36 };
     */
    function min(collection, iteratee, thisArg) {
      iteratee = isIterateeCall(collection, iteratee, thisArg) ? null : iteratee;

      var computed = Infinity,
          noIteratee = iteratee == null,
          isArr = noIteratee && isArray(collection),
          isStr = !isArr && isString(collection),
          result = computed;

      if (noIteratee && !isStr) {
        var index = -1,
            iterable = toIterable(collection),
            length = iterable.length;

        while (++index < length) {
          var value = iterable[index];
          if (value < result) {
            result = value;
          }
        }
      } else {
        iteratee = (noIteratee && isStr)
          ? charAtCallback
          : getCallback(iteratee, thisArg, 3);

        baseEach(collection, function(value, index, collection) {
          var current = iteratee(value, index, collection);
          if (current < computed || (current === Infinity && current === result)) {
            computed = current;
            result = value;
          }
        });
      }
      return result;
    }

    /**
     * Creates an array of elements split into two groups, the first of which
     * contains elements `predicate` returns truthy for, while the second of which
     * contains elements `predicate` returns falsey for. The predicate is bound
     * to `thisArg` and invoked with three arguments; (value, index|key, collection).
     *
     * If a property name is provided for `predicate` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `predicate` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [predicate=identity] The function invoked
     *  per iteration. If a property name or object is provided it is used to
     *  create a "_.pluck" or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the array of grouped elements.
     * @example
     *
     * _.partition([1, 2, 3], function(n) { return n % 2; });
     * // => [[1, 3], [2]]
     *
     * _.partition([1.2, 2.3, 3.4], function(n) { return this.floor(n) % 2; }, Math);
     * // => [[1, 3], [2]]
     *
     * var users = [
     *   { 'user': 'barney',  'age': 36 },
     *   { 'user': 'fred',    'age': 40, 'blocked': true },
     *   { 'user': 'pebbles', 'age': 1 }
     * ];
     *
     * // using "_.where" callback shorthand
     * _.map(_.partition(users, { 'age': 1 }), function(array) { return _.pluck(array, 'user'); });
     * // => [['pebbles'], ['barney', 'fred']]
     *
     * // using "_.pluck" callback shorthand
     * _.map(_.partition(users, 'blocked'), function(array) { return _.pluck(array, 'user'); });
     * // => [['fred'], ['barney', 'pebbles']]
     */
    var partition = createAggregator(function(result, value, key) {
      result[key ? 0 : 1].push(value);
    }, function() { return [[], []]; });

    /**
     * Retrieves the value of a specified property from all elements in the collection.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {string} key The name of the property to pluck.
     * @returns {Array} Returns the property values.
     * @example
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40 }
     * ];
     *
     * _.pluck(users, 'user');
     * // => ['barney', 'fred']
     *
     * var userIndex = _.indexBy(users, 'user');
     * _.pluck(userIndex, 'age');
     * // => [36, 40] (iteration order is not guaranteed)
     */
    function pluck(collection, key) {
      return map(collection, property(key));
    }

    /**
     * Reduces a collection to a value which is the accumulated result of running
     * each element in the collection through `iteratee`, where each successive
     * invocation is supplied the return value of the previous. If `accumulator`
     * is not provided the first element of the collection is used as the initial
     * value. The `iteratee` is bound to `thisArg`and invoked with four arguments;
     * (accumulator, value, index|key, collection).
     *
     * @static
     * @memberOf _
     * @alias foldl, inject
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} [iteratee=identity] The function invoked per iteration.
     * @param {*} [accumulator] The initial value.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {*} Returns the accumulated value.
     * @example
     *
     * var sum = _.reduce([1, 2, 3], function(sum, n) { return sum + n; });
     * // => 6
     *
     * var mapped = _.reduce({ 'a': 1, 'b': 2, 'c': 3 }, function(result, n, key) {
     *   result[key] = n * 3;
     *   return result;
     * }, {});
     * // => { 'a': 3, 'b': 6, 'c': 9 } (iteration order is not guaranteed)
     */
    function reduce(collection, iteratee, accumulator, thisArg) {
      var func = isArray(collection) ? arrayReduce : baseReduce;
      return func(collection, getCallback(iteratee, thisArg, 4), accumulator, arguments.length < 3, baseEach);
    }

    /**
     * This method is like `_.reduce` except that it iterates over elements of
     * `collection` from right to left.
     *
     * @static
     * @memberOf _
     * @alias foldr
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function} [iteratee=identity] The function invoked per iteration.
     * @param {*} [accumulator] The initial value.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {*} Returns the accumulated value.
     * @example
     *
     * var array = [[0, 1], [2, 3], [4, 5]];
     * _.reduceRight(array, function(flattened, other) { return flattened.concat(other); }, []);
     * // => [4, 5, 2, 3, 0, 1]
     */
    function reduceRight(collection, iteratee, accumulator, thisArg) {
      var func = isArray(collection) ? arrayReduceRight : baseReduce;
      return func(collection, getCallback(iteratee, thisArg, 4), accumulator, arguments.length < 3, baseEachRight);
    }

    /**
     * The opposite of `_.filter`; this method returns the elements of `collection`
     * that `predicate` does **not** return truthy for.
     *
     * If a property name is provided for `predicate` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `predicate` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [predicate=identity] The function invoked
     *  per iteration. If a property name or object is provided it is used to
     *  create a "_.pluck" or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Array} Returns the new filtered array.
     * @example
     *
     * var odds = _.reject([1, 2, 3, 4], function(n) { return n % 2 == 0; });
     * // => [1, 3]
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40, 'blocked': true }
     * ];
     *
     * // using "_.pluck" callback shorthand
     * _.reject(users, 'blocked');
     * // => [{ 'user': 'barney', 'age': 36 }]
     *
     * // using "_.where" callback shorthand
     * _.reject(users, { 'age': 36 });
     * // => [{ 'user': 'fred', 'age': 40, 'blocked': true }]
     */
    function reject(collection, predicate, thisArg) {
      var func = isArray(collection) ? arrayFilter : baseFilter;

      predicate = getCallback(predicate, thisArg, 3);
      return func(collection, function(value, index, collection) {
        return !predicate(value, index, collection);
      });
    }

    /**
     * Retrieves a random element or `n` random elements from a collection.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to sample.
     * @param {number} [n] The number of elements to sample.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {*} Returns the random sample(s).
     * @example
     *
     * _.sample([1, 2, 3, 4]);
     * // => 2
     *
     * _.sample([1, 2, 3, 4], 2);
     * // => [3, 1]
     */
    function sample(collection, n, guard) {
      if (guard || n == null) {
        collection = toIterable(collection);
        var length = collection.length;
        return length > 0 ? collection[baseRandom(0, length - 1)] : undefined;
      }
      var result = shuffle(collection);
      result.length = nativeMin(n < 0 ? 0 : (+n || 0), result.length);
      return result;
    }

    /**
     * Creates an array of shuffled values, using a version of the Fisher-Yates
     * shuffle. See [Wikipedia](http://en.wikipedia.org/wiki/Fisher-Yates_shuffle)
     * for more details.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to shuffle.
     * @returns {Array} Returns the new shuffled array.
     * @example
     *
     * _.shuffle([1, 2, 3, 4]);
     * // => [4, 1, 3, 2]
     */
    function shuffle(collection) {
      collection = toIterable(collection);

      var index = -1,
          length = collection.length,
          result = Array(length);

      while (++index < length) {
        var rand = baseRandom(0, index);
        if (index != rand) {
          result[index] = result[rand];
        }
        result[rand] = collection[index];
      }
      return result;
    }

    /**
     * Gets the size of the collection by returning `collection.length` for
     * array-like values or the number of own enumerable properties for objects.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to inspect.
     * @returns {number} Returns `collection.length` or number of own enumerable properties.
     * @example
     *
     * _.size([1, 2]);
     * // => 2
     *
     * _.size({ 'one': 1, 'two': 2, 'three': 3 });
     * // => 3
     *
     * _.size('pebbles');
     * // => 7
     */
    function size(collection) {
      var length = collection ? collection.length : 0;
      return (typeof length == 'number' && length > -1 && length <= MAX_SAFE_INTEGER)
        ? length
        : keys(collection).length;
    }

    /**
     * Checks if `predicate` returns truthy for **any** element of `collection`.
     * The function returns as soon as it finds a passing value and does not iterate
     * over the entire collection. The predicate is bound to `thisArg` and invoked
     * with three arguments; (value, index|key, collection).
     *
     * If a property name is provided for `predicate` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `predicate` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @alias any
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Function|Object|string} [predicate=identity] The function invoked
     *  per iteration. If a property name or object is provided it is used to
     *  create a "_.pluck" or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {boolean} Returns `true` if any element passes the predicate check,
     *  else `false`.
     * @example
     *
     * _.some([null, 0, 'yes', false], Boolean);
     * // => true
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40, 'blocked': true }
     * ];
     *
     * // using "_.pluck" callback shorthand
     * _.some(users, 'blocked');
     * // => true
     *
     * // using "_.where" callback shorthand
     * _.some(users, { 'age': 1 });
     * // => false
     */
    function some(collection, predicate, thisArg) {
      var func = isArray(collection) ? arraySome : baseSome;
      if (typeof predicate != 'function' || typeof thisArg != 'undefined') {
        predicate = getCallback(predicate, thisArg, 3);
      }
      return func(collection, predicate);
    }

    /**
     * Creates an array of elements, sorted in ascending order by the results of
     * running each element in a collection through `iteratee`. This method performs
     * a stable sort, that is, it preserves the original sort order of equal elements.
     * The `iteratee` is bound to `thisArg` and invoked with three arguments;
     * (value, index|key, collection).
     *
     * If a property name is provided for `iteratee` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an array of property names is provided for `iteratee` the collection
     * is sorted by each property value.
     *
     * If an object is provided for `iteratee` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to iterate over.
     * @param {Array|Function|Object|string} [iteratee=identity] The function
     *  invoked per iteration. If property name(s) or an object is provided it
     *  is used to create a "_.pluck" or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Array} Returns the new sorted array.
     * @example
     *
     * _.sortBy([1, 2, 3], function(n) { return Math.sin(n); });
     * // => [3, 1, 2]
     *
     * _.sortBy([1, 2, 3], function(n) { return this.sin(n); }, Math);
     * // => [3, 1, 2]
     *
     * var users = [
     *   { 'user': 'barney',  'age': 36 },
     *   { 'user': 'fred',    'age': 40 },
     *   { 'user': 'barney',  'age': 26 },
     *   { 'user': 'fred',    'age': 30 }
     * ];
     *
     * // using "_.pluck" callback shorthand
     * _.map(_.sortBy(users, 'age'), _.values);
     * // => [['barney', 26], ['fred', 30], ['barney', 36], ['fred', 40]]
     *
     * // sorting by multiple properties
     * _.map(_.sortBy(users, ['user', 'age']), _.values);
     * // = > [['barney', 26], ['barney', 36], ['fred', 30], ['fred', 40]]
     */
    function sortBy(collection, iteratee, thisArg) {
      iteratee = isIterateeCall(collection, iteratee, thisArg) ? null : iteratee;

      var index = -1,
          length = collection ? collection.length : 0,
          multi = iteratee && isArray(iteratee),
          result = [];

      if (typeof length == 'number' && length > -1 && length <= MAX_SAFE_INTEGER) {
        result.length = length;
      }
      if (!multi) {
        iteratee = getCallback(iteratee, thisArg, 3);
      }
      baseEach(collection, function(value, key, collection) {
        if (multi) {
          var length = iteratee.length,
              criteria = Array(length);

          while (length--) {
            criteria[length] = value == null ? undefined : value[iteratee[length]];
          }
        } else {
          criteria = iteratee(value, key, collection);
        }
        result[++index] = { 'criteria': criteria, 'index': index, 'value': value };
      });

      length = result.length;
      result.sort(multi ? compareMultipleAscending : compareAscending);
      while (length--) {
        result[length] = result[length].value;
      }
      return result;
    }

    /**
     * Converts `collection` to an array.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to convert.
     * @returns {Array} Returns the new converted array.
     * @example
     *
     * (function() { return _.toArray(arguments).slice(1); })(1, 2, 3, 4);
     * // => [2, 3, 4]
     */
    function toArray(collection) {
      var length = collection ? collection.length : 0;
      if (typeof length == 'number' && length > -1 && length <= MAX_SAFE_INTEGER) {
        return baseSlice(collection);
      }
      return values(collection);
    }

    /**
     * Performs a deep comparison between each element in `collection` and the
     * source object, returning an array of all elements that have equivalent
     * property values.
     *
     * @static
     * @memberOf _
     * @category Collection
     * @param {Array|Object|string} collection The collection to search.
     * @param {Object} source The object of property values to match.
     * @returns {Array} Returns the new filtered array.
     * @example
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36, 'employer': 'slate', 'pets': ['hoppy'] },
     *   { 'user': 'fred',   'age': 40, 'employer': 'slate', 'pets': ['baby puss', 'dino'] }
     * ];
     *
     * _.pluck(_.where(users, { 'age': 36 }), 'user');
     * // => ['barney']
     *
     * _.pluck(_.where(users, { 'pets': ['dino'] }), 'user');
     * // => ['fred']
     *
     * _.pluck(_.where(users, { 'employer': 'slate' }), 'user');
     * // => ['barney', 'fred']
     */
    function where(collection, source) {
      return filter(collection, matches(source));
    }

    /*------------------------------------------------------------------------*/

    /**
     * The opposite of `_.before`; this method creates a function that invokes
     * `func` only after it is called `n` times.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {number} n The number of calls before `func` is invoked.
     * @param {Function} func The function to restrict.
     * @returns {Function} Returns the new restricted function.
     * @example
     *
     * var saves = ['profile', 'settings'];
     *
     * var done = _.after(saves.length, function() {
     *   console.log('done saving!');
     * });
     *
     * _.forEach(saves, function(type) {
     *   asyncSave({ 'type': type, 'complete': done });
     * });
     * // => logs 'done saving!' after the two async saves have completed
     */
    function after(n, func) {
      if (!isFunction(func)) {
        if (isFunction(n)) {
          var temp = n;
          n = func;
          func = temp;
        } else {
          throw new TypeError(FUNC_ERROR_TEXT);
        }
      }
      n = nativeIsFinite(n = +n) ? n : 0;
      return function() {
        if (--n < 1) {
          return func.apply(this, arguments);
        }
      };
    }

    /**
     * Creates a function that invokes `func`, with the `this` binding and arguments
     * of the created function, while it is called less than `n` times. Subsequent
     * calls to the created function return the result of the last `func` invocation.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {number} n The number of calls at which `func` is no longer invoked.
     * @param {Function} func The function to restrict.
     * @returns {Function} Returns the new restricted function.
     * @example
     *
     * jQuery('#add').on('click', _.before(5, addContactToList));
     * // => allows adding up to 4 contacts to the list
     */
    function before(n, func) {
      var result;
      if (!isFunction(func)) {
        if (isFunction(n)) {
          var temp = n;
          n = func;
          func = temp;
        } else {
          throw new TypeError(FUNC_ERROR_TEXT);
        }
      }
      return function() {
        if (--n > 0) {
          result = func.apply(this, arguments);
        } else {
          func = null;
        }
        return result;
      };
    }

    /**
     * Creates a function that invokes `func` with the `this` binding of `thisArg`
     * and prepends any additional `bind` arguments to those provided to the bound
     * function.
     *
     * **Note:** Unlike native `Function#bind` this method does not set the `length`
     * property of bound functions.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to bind.
     * @param {*} [thisArg] The `this` binding of `func`.
     * @param {...*} [args] The arguments to be partially applied.
     * @returns {Function} Returns the new bound function.
     * @example
     *
     * var func = function(greeting) {
     *   return greeting + ' ' + this.user;
     * };
     *
     * func = _.bind(func, { 'user': 'fred' }, 'hi');
     * func();
     * // => 'hi fred'
     */
    function bind(func, thisArg) {
      if (arguments.length < 3) {
        return createWrapper(func, BIND_FLAG, null, thisArg);
      }
      var args = slice(arguments, 2),
          holders = replaceHolders(args, bind.placeholder);

      return basePartial(func, BIND_FLAG | PARTIAL_FLAG, args, holders, thisArg);
    }

    /**
     * Binds methods of an object to the object itself, overwriting the existing
     * method. Method names may be specified as individual arguments or as arrays
     * of method names. If no method names are provided all enumerable function
     * properties, own and inherited, of `object` are bound.
     *
     * **Note:** This method does not set the `length` property of bound functions.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Object} object The object to bind and assign the bound methods to.
     * @param {...(string|string[])} [methodNames] The object method names to bind,
     *  specified as individual method names or arrays of method names.
     * @returns {Object} Returns `object`.
     * @example
     *
     * var view = {
     *   'label': 'docs',
     *   'onClick': function() { console.log('clicked ' + this.label); }
     * };
     *
     * _.bindAll(view);
     * jQuery('#docs').on('click', view.onClick);
     * // => logs 'clicked docs' when the element is clicked
     */
    function bindAll(object) {
      return baseBindAll(object,
        arguments.length > 1
          ? baseFlatten(arguments, false, false, 1)
          : functions(object)
      );
    }

    /**
     * Creates a function that invokes the method at `object[key]` and prepends
     * any additional `bindKey` arguments to those provided to the bound function.
     * This method differs from `_.bind` by allowing bound functions to reference
     * methods that may be redefined or don't yet exist.
     * See [Peter Michaux's article](http://michaux.ca/articles/lazy-function-definition-pattern)
     * for more details.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Object} object The object the method belongs to.
     * @param {string} key The key of the method.
     * @param {...*} [args] The arguments to be partially applied.
     * @returns {Function} Returns the new bound function.
     * @example
     *
     * var object = {
     *   'user': 'fred',
     *   'greet': function(greeting) {
     *     return greeting + ' ' + this.user;
     *   }
     * };
     *
     * var func = _.bindKey(object, 'greet', 'hi');
     * func();
     * // => 'hi fred'
     *
     * object.greet = function(greeting) {
     *   return greeting + 'ya ' + this.user + '!';
     * };
     *
     * func();
     * // => 'hiya fred!'
     */
    function bindKey(object, key) {
      var bitmask = BIND_FLAG | BIND_KEY_FLAG;
      if (arguments.length > 2) {
        var args = slice(arguments, 2),
            holders = replaceHolders(args, bindKey.placeholder);
      }
      return args
        ? createWrapper(key, bitmask, null, object, args, holders)
        : createWrapper(key, bitmask, null, object);
    }

    /**
     * Creates a function that accepts one or more arguments of `func` that when
     * called either invokes `func` returning its result if all `func` arguments
     * have been provided, or returns a function that accepts one or more of the
     * remaining `func` arguments, and so on. The arity of `func` can be specified
     * if `func.length` is not sufficient.
     *
     * **Note:** This method does not set the `length` property of curried functions.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to curry.
     * @param {number} [arity=func.length] The arity of `func`.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Function} Returns the new curried function.
     * @example
     *
     * var curried = _.curry(function(a, b, c) {
     *   console.log([a, b, c]);
     * });
     *
     * curried(1)(2)(3);
     * // => [1, 2, 3]
     *
     * curried(1, 2)(3);
     * // => [1, 2, 3]
     *
     * curried(1, 2, 3);
     * // => [1, 2, 3]
     */
    function curry(func, arity, guard) {
      var result = baseCurry(func, CURRY_FLAG, guard ? null : arity);
      result.placeholder = curry.placeholder;
      return result;
    }

    /**
     * This method is like `_.curry` except that arguments are applied to `func`
     * in the manner of `_.partialRight` instead of `_.partial`.
     *
     * **Note:** This method does not set the `length` property of curried functions.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to curry.
     * @param {number} [arity=func.length] The arity of `func`.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Function} Returns the new curried function.
     * @example
     *
     * var curried = _.curryRight(function(a, b, c) {
     *   console.log([a, b, c]);
     * });
     *
     * curried(3)(2)(1);
     * // => [1, 2, 3]
     *
     * curried(2, 3)(1);
     * // => [1, 2, 3]
     *
     * curried(1, 2, 3);
     * // => [1, 2, 3]
     */
    function curryRight(func, arity, guard) {
      var result = baseCurry(func, CURRY_RIGHT_FLAG, guard ? null : arity);
      result.placeholder = curryRight.placeholder;
      return result;
    }

    /**
     * Creates a function that delays invoking `func` until after `wait` milliseconds
     * have elapsed since the last time it was invoked. The created function comes
     * with a `cancel` method to cancel delayed invocations. Provide an options
     * object to indicate that `func` should be invoked on the leading and/or
     * trailing edge of the `wait` timeout. Subsequent calls to the debounced
     * function return the result of the last `func` invocation.
     *
     * **Note:** If `leading` and `trailing` options are `true`, `func` is invoked
     * on the trailing edge of the timeout only if the the debounced function is
     * invoked more than once during the `wait` timeout.
     *
     * See [David Corbacho's article](http://drupalmotion.com/article/debounce-and-throttle-visual-explanation)
     * for details over the differences between `_.debounce` and `_.throttle`.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to debounce.
     * @param {number} wait The number of milliseconds to delay.
     * @param {Object} [options] The options object.
     * @param {boolean} [options.leading=false] Specify invoking on the leading
     *  edge of the timeout.
     * @param {number} [options.maxWait] The maximum time `func` is allowed to be
     *  delayed before it is invoked.
     * @param {boolean} [options.trailing=true] Specify invoking on the trailing
     *  edge of the timeout.
     * @returns {Function} Returns the new debounced function.
     * @example
     *
     * // avoid costly calculations while the window size is in flux
     * jQuery(window).on('resize', _.debounce(calculateLayout, 150));
     *
     * // invoke `sendMail` when the click event is fired, debouncing subsequent calls
     * jQuery('#postbox').on('click', _.debounce(sendMail, 300, {
     *   'leading': true,
     *   'trailing': false
     * });
     *
     * // ensure `batchLog` is invoked once after 1 second of debounced calls
     * var source = new EventSource('/stream');
     * jQuery(source).on('message', _.debounce(batchLog, 250, {
     *   'maxWait': 1000
     * }, false);
     *
     * // cancel a debounced call
     * var todoChanges = _.debounce(batchLog, 1000);
     * Object.observe(models.todo, todoChanges);
     *
     * Object.observe(models, function(changes) {
     *   if (_.find(changes, { 'user': 'todo', 'type': 'delete'})) {
     *     todoChanges.cancel();
     *   }
     * }, ['delete']);
     *
     * // ...at some point `models.todo` is changed
     * models.todo.completed = true;
     *
     * // ...before 1 second has passed `models.todo` is deleted
     * // which cancels the debounced `todoChanges` call
     * delete models.todo;
     */
    function debounce(func, wait, options) {
      var args,
          maxTimeoutId,
          result,
          stamp,
          thisArg,
          timeoutId,
          trailingCall,
          lastCalled = 0,
          maxWait = false,
          trailing = true;

      if (!isFunction(func)) {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      wait = wait < 0 ? 0 : wait;
      if (options === true) {
        var leading = true;
        trailing = false;
      } else if (isObject(options)) {
        leading = options.leading;
        maxWait = 'maxWait' in options && nativeMax(+options.maxWait || 0, wait);
        trailing = 'trailing' in options ? options.trailing : trailing;
      }

      function cancel() {
        if (timeoutId) {
          clearTimeout(timeoutId);
        }
        if (maxTimeoutId) {
          clearTimeout(maxTimeoutId);
        }
        maxTimeoutId = timeoutId = trailingCall = undefined;
      }

      function delayed() {
        var remaining = wait - (now() - stamp);
        if (remaining <= 0 || remaining > wait) {
          if (maxTimeoutId) {
            clearTimeout(maxTimeoutId);
          }
          var isCalled = trailingCall;
          maxTimeoutId = timeoutId = trailingCall = undefined;
          if (isCalled) {
            lastCalled = now();
            result = func.apply(thisArg, args);
            if (!timeoutId && !maxTimeoutId) {
              args = thisArg = null;
            }
          }
        } else {
          timeoutId = setTimeout(delayed, remaining);
        }
      }

      function maxDelayed() {
        if (timeoutId) {
          clearTimeout(timeoutId);
        }
        maxTimeoutId = timeoutId = trailingCall = undefined;
        if (trailing || (maxWait !== wait)) {
          lastCalled = now();
          result = func.apply(thisArg, args);
          if (!timeoutId && !maxTimeoutId) {
            args = thisArg = null;
          }
        }
      }

      function debounced() {
        args = arguments;
        stamp = now();
        thisArg = this;
        trailingCall = trailing && (timeoutId || !leading);

        if (maxWait === false) {
          var leadingCall = leading && !timeoutId;
        } else {
          if (!maxTimeoutId && !leading) {
            lastCalled = stamp;
          }
          var remaining = maxWait - (stamp - lastCalled),
              isCalled = remaining <= 0 || remaining > maxWait;

          if (isCalled) {
            if (maxTimeoutId) {
              maxTimeoutId = clearTimeout(maxTimeoutId);
            }
            lastCalled = stamp;
            result = func.apply(thisArg, args);
          }
          else if (!maxTimeoutId) {
            maxTimeoutId = setTimeout(maxDelayed, remaining);
          }
        }
        if (isCalled && timeoutId) {
          timeoutId = clearTimeout(timeoutId);
        }
        else if (!timeoutId && wait !== maxWait) {
          timeoutId = setTimeout(delayed, wait);
        }
        if (leadingCall) {
          isCalled = true;
          result = func.apply(thisArg, args);
        }
        if (isCalled && !timeoutId && !maxTimeoutId) {
          args = thisArg = null;
        }
        return result;
      }
      debounced.cancel = cancel;
      return debounced;
    }

    /**
     * Defers invoking the `func` until the current call stack has cleared. Any
     * additional arguments are provided to `func` when it is invoked.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to defer.
     * @param {...*} [args] The arguments to invoke the function with.
     * @returns {number} Returns the timer id.
     * @example
     *
     * _.defer(function(text) { console.log(text); }, 'deferred');
     * // logs 'deferred' after one or more milliseconds
     */
    function defer(func) {
      if (!isFunction(func)) {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      var args = slice(arguments, 1);
      return setTimeout(function() { func.apply(undefined, args); }, 1);
    }

    /**
     * Invokes `func` after `wait` milliseconds. Any additional arguments are
     * provided to `func` when it is invoked.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to delay.
     * @param {number} wait The number of milliseconds to delay invocation.
     * @param {...*} [args] The arguments to invoke the function with.
     * @returns {number} Returns the timer id.
     * @example
     *
     * _.delay(function(text) { console.log(text); }, 1000, 'later');
     * // => logs 'later' after one second
     */
    function delay(func, wait) {
      if (!isFunction(func)) {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      var args = slice(arguments, 2);
      return setTimeout(function() { func.apply(undefined, args); }, wait);
    }

    /**
     * Creates a function that invokes the provided functions with the `this`
     * binding of the created function, where each successive invocation is
     * supplied the return value of the previous.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {...Function} [funcs] Functions to invoke.
     * @returns {Function} Returns the new function.
     * @example
     *
     * function add(x, y) {
     *   return x + y;
     * }
     *
     * function square(n) {
     *   return n * n;
     * }
     *
     * var addSquare = _.flow(add, square);
     * addSquare(1, 2);
     * // => 9
     */
    function flow() {
      var funcs = arguments,
          length = funcs.length;

      if (!length) {
        return function() {};
      }
      if (!arrayEvery(funcs, isFunction)) {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      return function() {
        var index = 0,
            result = funcs[index].apply(this, arguments);

        while (++index < length) {
          result = funcs[index].call(this, result);
        }
        return result;
      };
    }

    /**
     * This method is like `_.flow` except that it creates a function that
     * invokes the provided functions from right to left.
     *
     * @static
     * @memberOf _
     * @alias backflow, compose
     * @category Function
     * @param {...Function} [funcs] Functions to invoke.
     * @returns {Function} Returns the new function.
     * @example
     *
     * function add(x, y) {
     *   return x + y;
     * }
     *
     * function square(n) {
     *   return n * n;
     * }
     *
     * var addSquare = _.flowRight(square, add);
     * addSquare(1, 2);
     * // => 9
     */
    function flowRight() {
      var funcs = arguments,
          fromIndex = funcs.length - 1;

      if (fromIndex < 0) {
        return function() {};
      }
      if (!arrayEvery(funcs, isFunction)) {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      return function() {
        var index = fromIndex,
            result = funcs[index].apply(this, arguments);

        while (index--) {
          result = funcs[index].call(this, result);
        }
        return result;
      };
    }

    /**
     * Creates a function that memoizes the result of `func`. If `resolver` is
     * provided it determines the cache key for storing the result based on the
     * arguments provided to the memoized function. By default, the first argument
     * provided to the memoized function is used as the cache key. The `func` is
     * invoked with the `this` binding of the memoized function. The result cache
     * is exposed as the `cache` property on the memoized function.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to have its output memoized.
     * @param {Function} [resolver] The function to resolve the cache key.
     * @returns {Function} Returns the new memoizing function.
     * @example
     *
     * var fibonacci = _.memoize(function(n) {
     *   return n < 2 ? n : fibonacci(n - 1) + fibonacci(n - 2);
     * });
     *
     * fibonacci(9)
     * // => 34
     *
     * // modifying the result cache
     * var upperCase = _.memoize(function(string) {
     *   return string.toUpperCase();
     * });
     *
     * upperCase('fred');
     * // => 'FRED'
     *
     * upperCase.cache.fred = 'BARNEY'
     * upperCase('fred');
     * // => 'BARNEY'
     */
    function memoize(func, resolver) {
      if (!isFunction(func) || (resolver && !isFunction(resolver))) {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      var memoized = function() {
        var key = resolver ? resolver.apply(this, arguments) : arguments[0];
        if (key == '__proto__') {
          return func.apply(this, arguments);
        }
        var cache = memoized.cache;
        return hasOwnProperty.call(cache, key)
          ? cache[key]
          : (cache[key] = func.apply(this, arguments));
      };
      memoized.cache = {};
      return memoized;
    }

    /**
     * Creates a function that negates the result of the predicate `func`. The
     * `func` predicate is invoked with the `this` binding and arguments of the
     * created function.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} predicate The predicate to negate.
     * @returns {Function} Returns the new function.
     * @example
     *
     * function isEven(n) {
     *   return n % 2 == 0;
     * }
     *
     * _.filter([1, 2, 3, 4, 5, 6], _.negate(isEven));
     * // => [1, 3, 5]
     */
    function negate(predicate) {
      if (!isFunction(predicate)) {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      return function() {
        return !predicate.apply(this, arguments);
      };
    }

    /**
     * Creates a function that is restricted to invoking `func` once. Repeat calls
     * to the function return the value of the first call. The `func` is invoked
     * with the `this` binding of the created function.
     *
     * @static
     * @memberOf _
     * @type Function
     * @category Function
     * @param {Function} func The function to restrict.
     * @returns {Function} Returns the new restricted function.
     * @example
     *
     * var initialize = _.once(createApplication);
     * initialize();
     * initialize();
     * // `initialize` invokes `createApplication` once
     */
    var once = partial(before, 2);

    /**
     * Creates a function that invokes `func` with `partial` arguments prepended
     * to those provided to the new function. This method is similar to `_.bind`
     * except it does **not** alter the `this` binding.
     *
     * **Note:** This method does not set the `length` property of partially
     * applied functions.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to partially apply arguments to.
     * @param {...*} [args] The arguments to be partially applied.
     * @returns {Function} Returns the new partially applied function.
     * @example
     *
     * var greet = function(greeting, name) { return greeting + ' ' + name; };
     * var sayHelloTo = _.partial(greet, 'hello');
     * sayHelloTo('fred');
     * // => 'hello fred'
     */
    function partial(func) {
      var args = slice(arguments, 1),
          holders = replaceHolders(args, partial.placeholder);

      return basePartial(func, PARTIAL_FLAG, args, holders);
    }

    /**
     * This method is like `_.partial` except that partially applied arguments
     * are appended to those provided to the new function.
     *
     * **Note:** This method does not set the `length` property of partially applied
     * functions.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to partially apply arguments to.
     * @param {...*} [args] The arguments to be partially applied.
     * @returns {Function} Returns the new partially applied function.
     * @example
     *
     * var greet = function(greeting, name) { return greeting + ' ' + name; };
     * var greetFred = _.partialRight(greet, 'fred');
     * greetFred('hello');
     * // => 'hello fred'
     *
     * // create a deep `_.defaults`
     * var defaultsDeep = _.partialRight(_.merge, function deep(value, other) {
     *   return _.merge(value, other, deep);
     * });
     *
     * var object = { 'a': { 'b': { 'c': 1 } } },
     *     source = { 'a': { 'b': { 'c': 2, 'd': 2 } } };
     *
     * defaultsDeep(object, source);
     * // => { 'a': { 'b': { 'c': 1, 'd': 2 } } }
     */
    function partialRight(func) {
      var args = slice(arguments, 1),
          holders = replaceHolders(args, partialRight.placeholder);

      return basePartial(func, PARTIAL_RIGHT_FLAG, args, holders);
    }

    /**
     * Creates a function that only invokes `func` at most once per every `wait`
     * milliseconds. The created function comes with a `cancel` method to cancel
     * delayed invocations. Provide an options object to indicate that `func`
     * should be invoked on the leading and/or trailing edge of the `wait` timeout.
     * Subsequent calls to the throttled function return the result of the last
     * `func` call.
     *
     * **Note:** If `leading` and `trailing` options are `true`, `func` is invoked
     * on the trailing edge of the timeout only if the the throttled function is
     * invoked more than once during the `wait` timeout.
     *
     * See [David Corbacho's article](http://drupalmotion.com/article/debounce-and-throttle-visual-explanation)
     * for details over the differences between `_.throttle` and `_.debounce`.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {Function} func The function to throttle.
     * @param {number} wait The number of milliseconds to throttle invocations to.
     * @param {Object} [options] The options object.
     * @param {boolean} [options.leading=true] Specify invoking on the leading
     *  edge of the timeout.
     * @param {boolean} [options.trailing=true] Specify invoking on the trailing
     *  edge of the timeout.
     * @returns {Function} Returns the new throttled function.
     * @example
     *
     * // avoid excessively updating the position while scrolling
     * jQuery(window).on('scroll', _.throttle(updatePosition, 100));
     *
     * // invoke `renewToken` when the click event is fired, but not more than once every 5 minutes
     * var throttled =  _.throttle(renewToken, 300000, { 'trailing': false })
     * jQuery('.interactive').on('click', throttled);
     *
     * // cancel a trailing throttled call
     * jQuery(window).on('popstate', throttled.cancel);
     */
    function throttle(func, wait, options) {
      var leading = true,
          trailing = true;

      if (!isFunction(func)) {
        throw new TypeError(FUNC_ERROR_TEXT);
      }
      if (options === false) {
        leading = false;
      } else if (isObject(options)) {
        leading = 'leading' in options ? !!options.leading : leading;
        trailing = 'trailing' in options ? !!options.trailing : trailing;
      }
      debounceOptions.leading = leading;
      debounceOptions.maxWait = +wait;
      debounceOptions.trailing = trailing;
      return debounce(func, wait, debounceOptions);
    }

    /**
     * Creates a function that provides `value` to the wrapper function as its
     * first argument. Any additional arguments provided to the function are
     * appended to those provided to the wrapper function. The wrapper is invoked
     * with the `this` binding of the created function.
     *
     * @static
     * @memberOf _
     * @category Function
     * @param {*} value The value to wrap.
     * @param {Function} wrapper The wrapper function.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var p = _.wrap(_.escape, function(func, text) {
     *   return '<p>' + func(text) + '</p>';
     * });
     *
     * p('fred, barney, & pebbles');
     * // => '<p>fred, barney, &amp; pebbles</p>'
     */
    function wrap(value, wrapper) {
      return basePartial(wrapper, PARTIAL_FLAG, [value], []);
    }

    /*------------------------------------------------------------------------*/

    /**
     * Creates a clone of `value`. If `isDeep` is `true` nested objects are cloned,
     * otherwise they are assigned by reference. If `customizer` is provided it is
     * invoked to produce the cloned values. If `customizer` returns `undefined`
     * cloning is handled by the method instead. The `customizer` is bound to
     * `thisArg` and invoked with two argument; (value, index|key).
     *
     * **Note:** This method is loosely based on the structured clone algorithm. Functions
     * and DOM nodes are **not** cloned. The enumerable properties of `arguments` objects and
     * objects created by constructors other than `Object` are cloned to plain `Object` objects.
     * See the [HTML5 specification](http://www.w3.org/TR/html5/infrastructure.html#internal-structured-cloning-algorithm)
     * for more details.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to clone.
     * @param {boolean} [isDeep=false] Specify a deep clone.
     * @param {Function} [customizer] The function to customize cloning values.
     * @param {*} [thisArg] The `this` binding of `customizer`.
     * @returns {*} Returns the cloned value.
     * @example
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40 }
     * ];
     *
     * var shallow = _.clone(users);
     * shallow[0] === users[0];
     * // => true
     *
     * var deep = _.clone(users, true);
     * deep[0] === users[0];
     * // => false
     *
     * _.mixin({
     *   'clone': _.partialRight(_.clone, function(value) {
     *     return _.isElement(value) ? value.cloneNode(false) : undefined;
     *   })
     * });
     *
     * var clone = _.clone(document.body);
     * clone.childNodes.length;
     * // => 0
     */
    function clone(value, isDeep, customizer, thisArg) {
      // juggle arguments
      if (typeof isDeep != 'boolean' && isDeep != null) {
        thisArg = customizer;
        customizer = isIterateeCall(value, isDeep, thisArg) ? null : isDeep;
        isDeep = false;
      }
      customizer = typeof customizer == 'function' && baseCallback(customizer, thisArg, 1);
      return baseClone(value, isDeep, customizer);
    }

    /**
     * Creates a deep clone of `value`. If `customizer` is provided it is invoked
     * to produce the cloned values. If `customizer` returns `undefined` cloning
     * is handled by the method instead. The `customizer` is bound to `thisArg`
     * and invoked with two argument; (value, index|key).
     *
     * **Note:** This method is loosely based on the structured clone algorithm. Functions
     * and DOM nodes are **not** cloned. The enumerable properties of `arguments` objects and
     * objects created by constructors other than `Object` are cloned to plain `Object` objects.
     * See the [HTML5 specification](http://www.w3.org/TR/html5/infrastructure.html#internal-structured-cloning-algorithm)
     * for more details.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to deep clone.
     * @param {Function} [customizer] The function to customize cloning values.
     * @param {*} [thisArg] The `this` binding of `customizer`.
     * @returns {*} Returns the deep cloned value.
     * @example
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40 }
     * ];
     *
     * var deep = _.cloneDeep(users);
     * deep[0] === users[0];
     * // => false
     *
     * var view = {
     *   'label': 'docs',
     *   'node': element
     * };
     *
     * var clone = _.cloneDeep(view, function(value) {
     *   return _.isElement(value) ? value.cloneNode(true) : undefined;
     * });
     *
     * clone.node == view.node;
     * // => false
     */
    function cloneDeep(value, customizer, thisArg) {
      customizer = typeof customizer == 'function' && baseCallback(customizer, thisArg, 1);
      return baseClone(value, true, customizer);
    }

    /**
     * Checks if `value` is classified as an `arguments` object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is an `arguments` object, else `false`.
     * @example
     *
     * (function() { return _.isArguments(arguments); })();
     * // => true
     *
     * _.isArguments([1, 2, 3]);
     * // => false
     */
    function isArguments(value) {
      var length = (value && typeof value == 'object') ? value.length : undefined;
      return (typeof length == 'number' && length > -1 && length <= MAX_SAFE_INTEGER &&
        toString.call(value) == argsClass) || false;
    }

    /**
     * Checks if `value` is classified as an `Array` object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isArray([1, 2, 3]);
     * // => true
     *
     * (function() { return _.isArray(arguments); })();
     * // => false
     */
    var isArray = nativeIsArray || function(value) {
      return (value && typeof value == 'object' && typeof value.length == 'number' &&
        toString.call(value) == arrayClass) || false;
    };

    /**
     * Checks if `value` is classified as a boolean primitive or object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isBoolean(false);
     * // => true
     *
     * _.isBoolean(null);
     * // => false
     */
    function isBoolean(value) {
      return (value === true || value === false || value && typeof value == 'object' &&
        toString.call(value) == boolClass) || false;
    }

    /**
     * Checks if `value` is classified as a `Date` object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isDate(new Date);
     * // => true
     *
     * _.isDate('Mon April 23 2012');
     * // => false
     */
    function isDate(value) {
      return (value && typeof value == 'object' && toString.call(value) == dateClass) || false;
    }

    /**
     * Checks if `value` is a DOM element.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is a DOM element, else `false`.
     * @example
     *
     * _.isElement(document.body);
     * // => true
     *
     * _.isElement('<body>');
     * // => false
     */
    function isElement(value) {
      return (value && typeof value == 'object' && value.nodeType === 1 &&
        toString.call(value).indexOf('Element') > -1) || false;
    }
    // fallback for environments without DOM support
    if (!support.dom) {
      isElement = function(value) {
        return (value && typeof value == 'object' && value.nodeType === 1 && !isPlainObject(value)) || false;
      };
    }

    /**
     * Checks if a collection is empty. A value is considered empty unless it is
     * an array-like value with a length greater than `0` or an object with own
     * enumerable properties.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {Array|Object|string} value The value to inspect.
     * @returns {boolean} Returns `true` if `value` is empty, else `false`.
     * @example
     *
     * _.isEmpty(null);
     * // => true
     *
     * _.isEmpty(true);
     * // => true
     *
     * _.isEmpty(1);
     * // => true
     *
     * _.isEmpty([1, 2, 3]);
     * // => false
     *
     * _.isEmpty({ 'a': 1 });
     * // => false
     */
    function isEmpty(value) {
      if (value == null) {
        return true;
      }
      var length = value.length;
      if ((typeof length == 'number' && length > -1 && length <= MAX_SAFE_INTEGER) &&
          (isArray(value) || isString(value) || isArguments(value) ||
            (typeof value == 'object' && isFunction(value.splice)))) {
        return !length;
      }
      return !keys(value).length;
    }

    /**
     * Performs a deep comparison between two values to determine if they are
     * equivalent. If `customizer` is provided it is invoked to compare values.
     * If `customizer` returns `undefined` comparisons are handled by the method
     * instead. The `customizer` is bound to `thisArg` and invoked with three
     * arguments; (value, other, key).
     *
     * **Note:** This method supports comparing arrays, booleans, `Date` objects,
     * numbers, `Object` objects, regexes, and strings. Functions and DOM nodes
     * are **not** supported. Provide a customizer function to extend support
     * for comparing other values.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to compare to `other`.
     * @param {*} other The value to compare to `value`.
     * @param {Function} [customizer] The function to customize comparing values.
     * @param {*} [thisArg] The `this` binding of `customizer`.
     * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
     * @example
     *
     * var object = { 'user': 'fred' };
     * var other = { 'user': 'fred' };
     *
     * object == other;
     * // => false
     *
     * _.isEqual(object, other);
     * // => true
     *
     * var words = ['hello', 'goodbye'];
     * var otherWords = ['hi', 'goodbye'];
     *
     * _.isEqual(words, otherWords, function() {
     *   return _.every(arguments, _.bind(RegExp.prototype.test, /^h(?:i|ello)$/)) || undefined;
     * });
     * // => true
     */
    function isEqual(value, other, customizer, thisArg) {
      customizer = typeof customizer == 'function' && baseCallback(customizer, thisArg, 3);
      return (!customizer && isStrictComparable(value) && isStrictComparable(other))
        ? value === other
        : baseIsEqual(value, other, customizer);
    }

    /**
     * Checks if `value` is an `Error`, `EvalError`, `RangeError`, `ReferenceError`,
     * `SyntaxError`, `TypeError`, or `URIError` object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is an error object, else `false`.
     * @example
     *
     * _.isError(new Error);
     * // => true
     *
     * _.isError(Error);
     * // => false
     */
    function isError(value) {
      return (value && typeof value == 'object' && toString.call(value) == errorClass) || false;
    }

    /**
     * Checks if `value` is a finite primitive number.
     *
     * **Note:** This method is based on ES6 `Number.isFinite`. See the
     * [ES6 spec](http://people.mozilla.org/~jorendorff/es6-draft.html#sec-number.isfinite)
     * for more details.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is a finite number, else `false`.
     * @example
     *
     * _.isFinite(10);
     * // => true
     *
     * _.isFinite('10');
     * // => false
     *
     * _.isFinite(true);
     * // => false
     *
     * _.isFinite(Object(10));
     * // => false
     *
     * _.isFinite(Infinity);
     * // => false
     */
    var isFinite = nativeNumIsFinite || function(value) {
      return typeof value == 'number' && nativeIsFinite(value);
    };

    /**
     * Checks if `value` is classified as a `Function` object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isFunction(_);
     * // => true
     *
     * _.isFunction(/abc/);
     * // => false
     */
    function isFunction(value) {
      // avoid a Chakra bug in IE 11
      // https://github.com/jashkenas/underscore/issues/1621
      return typeof value == 'function' || false;
    }

    /**
     * Checks if `value` is the language type of `Object`.
     * (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)
     *
     * **Note:** See the [ES5 spec](http://es5.github.io/#x8) for more details.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is an object, else `false`.
     * @example
     *
     * _.isObject({});
     * // => true
     *
     * _.isObject([1, 2, 3]);
     * // => true
     *
     * _.isObject(1);
     * // => false
     */
    function isObject(value) {
      // avoid a V8 bug in Chrome 19-20
      // https://code.google.com/p/v8/issues/detail?id=2291
      var type = typeof value;
      return type == 'function' || (value && type == 'object') || false;
    }

    /**
     * Checks if `value` is `NaN`.
     *
     * **Note:** This method is not the same as native `isNaN` which returns `true`
     * for `undefined` and other non-numeric values. See the [ES5 spec](http://es5.github.io/#x15.1.2.4)
     * for more details.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is `NaN`, else `false`.
     * @example
     *
     * _.isNaN(NaN);
     * // => true
     *
     * _.isNaN(new Number(NaN));
     * // => true
     *
     * isNaN(undefined);
     * // => true
     *
     * _.isNaN(undefined);
     * // => false
     */
    function isNaN(value) {
      // `NaN` as a primitive is the only value that is not equal to itself
      // (perform the `[[Class]]` check first to avoid errors with some host objects in IE)
      return isNumber(value) && value != +value;
    }

    /**
     * Checks if `value` is a native function.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is a native function, else `false`.
     * @example
     *
     * _.isNative(Array.prototype.push);
     * // => true
     *
     * _.isNative(_);
     * // => false
     */
    function isNative(value) {
      if (isFunction(value)) {
        return reNative.test(fnToString.call(value));
      }
      return (value && typeof value == 'object' && reHostCtor.test(value)) || false;
    }

    /**
     * Checks if `value` is `null`.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is `null`, else `false`.
     * @example
     *
     * _.isNull(null);
     * // => true
     *
     * _.isNull(void 0);
     * // => false
     */
    function isNull(value) {
      return value === null;
    }

    /**
     * Checks if `value` is classified as a `Number` primitive or object.
     *
     * **Note:** To exclude `Infinity`, `-Infinity`, and `NaN`, which are classified
     * as numbers, use the `_.isFinite` method.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isNumber(8.4);
     * // => true
     *
     * _.isNumber(NaN);
     * // => true
     *
     * _.isNumber('8.4');
     * // => false
     */
    function isNumber(value) {
      var type = typeof value;
      return type == 'number' || (value && type == 'object' && toString.call(value) == numberClass) || false;
    }

    /**
     * Checks if `value` is an object created by the `Object` constructor or has
     * a `[[Prototype]]` of `null`.
     *
     * **Note:** This method assumes objects created by the `Object` constructor
     * have no inherited enumerable properties.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is a plain object, else `false`.
     * @example
     *
     * function Shape() {
     *   this.x = 0;
     *   this.y = 0;
     * }
     *
     * _.isPlainObject(new Shape);
     * // => false
     *
     * _.isPlainObject([1, 2, 3]);
     * // => false
     *
     * _.isPlainObject({ 'x': 0, 'y': 0 });
     * // => true
     *
     * _.isPlainObject(Object.create(null));
     * // => true
     */
    var isPlainObject = !getPrototypeOf ? shimIsPlainObject : function(value) {
      if (!(value && toString.call(value) == objectClass)) {
        return false;
      }
      var valueOf = value.valueOf,
          objProto = isNative(valueOf) && (objProto = getPrototypeOf(valueOf)) && getPrototypeOf(objProto);

      return objProto
        ? (value == objProto || getPrototypeOf(value) == objProto)
        : shimIsPlainObject(value);
    };

    /**
     * Checks if `value` is classified as a `RegExp` object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isRegExp(/abc/);
     * // => true
     *
     * _.isRegExp('/abc/');
     * // => false
     */
    function isRegExp(value) {
      return (value && typeof value == 'object' && toString.call(value) == regexpClass) || false;
    }

    /**
     * Checks if `value` is classified as a `String` primitive or object.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is correctly classified, else `false`.
     * @example
     *
     * _.isString('abc');
     * // => true
     *
     * _.isString(1);
     * // => false
     */
    function isString(value) {
      return typeof value == 'string' || (value && typeof value == 'object' &&
        toString.call(value) == stringClass) || false;
    }

    /**
     * Checks if `value` is `undefined`.
     *
     * @static
     * @memberOf _
     * @category Lang
     * @param {*} value The value to check.
     * @returns {boolean} Returns `true` if `value` is `undefined`, else `false`.
     * @example
     *
     * _.isUndefined(void 0);
     * // => true
     *
     * _.isUndefined(null);
     * // => false
     */
    function isUndefined(value) {
      return typeof value == 'undefined';
    }

    /*------------------------------------------------------------------------*/

    /**
     * Assigns own enumerable properties of source object(s) to the destination
     * object. Subsequent sources overwrite property assignments of previous sources.
     * If `customizer` is provided it is invoked to produce the assigned values.
     * The `customizer` is bound to `thisArg` and invoked with five arguments;
     * (objectValue, sourceValue, key, object, source).
     *
     * @static
     * @memberOf _
     * @alias extend
     * @category Object
     * @param {Object} object The destination object.
     * @param {...Object} [sources] The source objects.
     * @param {Function} [customizer] The function to customize assigning values.
     * @param {*} [thisArg] The `this` binding of `customizer`.
     * @returns {Object} Returns the destination object.
     * @example
     *
     * _.assign({ 'user': 'fred' }, { 'age': 40 }, { 'employer': 'slate' });
     * // => { 'user': 'fred', 'age': 40, 'employer': 'slate' }
     *
     * var defaults = _.partialRight(_.assign, function(value, other) {
     *   return typeof value == 'undefined' ? other : value;
     * });
     *
     * defaults({ 'user': 'barney' }, { 'age': 36 }, { 'user': 'fred', 'employer': 'slate' });
     * // => { 'user': 'barney', 'age': 36, 'employer': 'slate' }
     */
    var assign = createAssigner(baseAssign);

    /**
     * Creates an object that inherits from the given `prototype` object. If a
     * `properties` object is provided its own enumerable properties are assigned
     * to the created object.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} prototype The object to inherit from.
     * @param {Object} [properties] The properties to assign to the object.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Object} Returns the new object.
     * @example
     *
     * function Shape() {
     *   this.x = 0;
     *   this.y = 0;
     * }
     *
     * function Circle() {
     *   Shape.call(this);
     * }
     *
     * Circle.prototype = _.create(Shape.prototype, { 'constructor': Circle });
     *
     * var circle = new Circle;
     * circle instanceof Circle;
     * // => true
     *
     * circle instanceof Shape;
     * // => true
     */
    function create(prototype, properties, guard) {
      var result = baseCreate(prototype);
      properties = guard ? null : properties;
      return properties ? baseAssign(result, properties) : result;
    }

    /**
     * Assigns own enumerable properties of source object(s) to the destination
     * object for all destination properties that resolve to `undefined`. Once a
     * property is set, additional defaults of the same property are ignored.
     *
     * **Note:** See the [documentation example of `_.partialRight`](http://lodash.com/docs#partialRight)
     * for a deep version of this method.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The destination object.
     * @param {...Object} [sources] The source objects.
     * @returns {Object} Returns the destination object.
     * @example
     *
     * _.defaults({ 'user': 'barney' }, { 'age': 36 }, { 'user': 'fred', 'employer': 'slate' });
     * // => { 'user': 'barney', 'age': 36, 'employer': 'slate' }
     */
    function defaults(object) {
      if (object == null) {
        return object;
      }
      var args = baseSlice(arguments);
      args.push(assignDefaults);
      return assign.apply(undefined, args);
    }

    /**
     * This method is like `_.findIndex` except that it returns the key of the
     * first element `predicate` returns truthy for, instead of the element itself.
     *
     * If a property name is provided for `predicate` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `predicate` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to search.
     * @param {Function|Object|string} [predicate=identity] The function invoked
     *  per iteration. If a property name or object is provided it is used to
     *  create a "_.pluck" or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {string|undefined} Returns the key of the matched element, else `undefined`.
     * @example
     *
     * var users = {
     *   'barney': { 'age': 36 },
     *   'fred': { 'age': 40, 'blocked': true },
     *   'pebbles': { 'age': 1 }
     * };
     *
     * _.findKey(users, function(chr) {
     *   return chr.age < 40;
     * });
     * // => 'barney' (iteration order is not guaranteed)
     *
     * // using "_.where" callback shorthand
     * _.findKey(users, { 'age': 1 });
     * // => 'pebbles'
     *
     * // using "_.pluck" callback shorthand
     * _.findKey(users, 'blocked');
     * // => 'fred'
     */
    function findKey(object, predicate, thisArg) {
      predicate = getCallback(predicate, thisArg, 3);
      return baseFind(object, predicate, baseForOwn, true);
    }

    /**
     * This method is like `_.findKey` except that it iterates over elements of
     * a collection in the opposite order.
     *
     * If a property name is provided for `predicate` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `predicate` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to search.
     * @param {Function|Object|string} [predicate=identity] The function invoked
     *  per iteration. If a property name or object is provided it is used to
     *  create a "_.pluck" or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {string|undefined} Returns the key of the matched element, else `undefined`.
     * @example
     *
     * var users = {
     *   'barney': { 'age': 36, 'blocked': true },
     *   'fred': { 'age': 40 },
     *   'pebbles': { 'age': 1, 'blocked': true }
     * };
     *
     * _.findLastKey(users, function(chr) {
     *   return chr.age < 40;
     * });
     * // => returns `pebbles`, assuming `_.findKey` returns `barney`
     *
     * // using "_.where" callback shorthand
     * _.findLastKey(users, { 'age': 40 });
     * // => 'fred'
     *
     * // using "_.pluck" callback shorthand
     * _.findLastKey(users, 'blocked');
     * // => 'pebbles'
     */
    function findLastKey(object, predicate, thisArg) {
      predicate = getCallback(predicate, thisArg, 3);
      return baseFind(object, predicate, baseForOwnRight, true);
    }

    /**
     * Iterates over own and inherited enumerable properties of an object invoking
     * `iteratee` for each property. The `iteratee` is bound to `thisArg` and invoked
     * with three arguments; (value, key, object). Iterator functions may exit
     * iteration early by explicitly returning `false`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to iterate over.
     * @param {Function} [iteratee=identity] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns `object`.
     * @example
     *
     * function Shape() {
     *   this.x = 0;
     *   this.y = 0;
     * }
     *
     * Shape.prototype.z = 0;
     *
     * _.forIn(new Shape, function(value, key) {
     *   console.log(key);
     * });
     * // => logs 'x', 'y', and 'z' (iteration order is not guaranteed)
     */
    function forIn(object, iteratee, thisArg) {
      if (typeof iteratee != 'function' || typeof thisArg != 'undefined') {
        iteratee = baseCallback(iteratee, thisArg, 3);
      }
      return baseFor(object, iteratee, keysIn);
    }

    /**
     * This method is like `_.forIn` except that it iterates over properties of
     * `object` in the opposite order.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to iterate over.
     * @param {Function} [iteratee=identity] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns `object`.
     * @example
     *
     * function Shape() {
     *   this.x = 0;
     *   this.y = 0;
     * }
     *
     * Shape.prototype.z = 0;
     *
     * _.forInRight(new Shape, function(value, key) {
     *   console.log(key);
     * });
     * // => logs 'z', 'y', and 'x' assuming `_.forIn ` logs 'x', 'y', and 'z'
     */
    function forInRight(object, iteratee, thisArg) {
      iteratee = baseCallback(iteratee, thisArg, 3);
      return baseForRight(object, iteratee, keysIn);
    }

    /**
     * Iterates over own enumerable properties of an object invoking `iteratee`
     * for each property. The `iteratee` is bound to `thisArg` and invoked with
     * three arguments; (value, key, object). Iterator functions may exit iteration
     * early by explicitly returning `false`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to iterate over.
     * @param {Function} [iteratee=identity] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns `object`.
     * @example
     *
     * _.forOwn({ '0': 'zero', '1': 'one', 'length': 2 }, function(n, key) {
     *   console.log(key);
     * });
     * // => logs '0', '1', and 'length' (iteration order is not guaranteed)
     */
    function forOwn(object, iteratee, thisArg) {
      if (typeof iteratee != 'function' || typeof thisArg != 'undefined') {
        iteratee = baseCallback(iteratee, thisArg, 3);
      }
      return baseForOwn(object, iteratee);
    }

    /**
     * This method is like `_.forOwn` except that it iterates over properties of
     * `object` in the opposite order.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to iterate over.
     * @param {Function} [iteratee=identity] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns `object`.
     * @example
     *
     * _.forOwnRight({ '0': 'zero', '1': 'one', 'length': 2 }, function(n, key) {
     *   console.log(key);
     * });
     * // => logs 'length', '1', and '0' assuming `_.forOwn` logs '0', '1', and 'length'
     */
    function forOwnRight(object, iteratee, thisArg) {
      iteratee = baseCallback(iteratee, thisArg, 3);
      return baseForRight(object, iteratee, keys);
    }

    /**
     * Creates an array of function property names from all enumerable properties,
     * own and inherited, of `object`.
     *
     * @static
     * @memberOf _
     * @alias methods
     * @category Object
     * @param {Object} object The object to inspect.
     * @returns {Array} Returns the new array of property names.
     * @example
     *
     * _.functions(_);
     * // => ['all', 'any', 'bind', ...]
     */
    function functions(object) {
      return baseFunctions(object, keysIn(object));
    }

    /**
     * Checks if the specified property name exists as a direct property of `object`,
     * instead of an inherited property.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to inspect.
     * @param {string} key The name of the property to check.
     * @returns {boolean} Returns `true` if key is a direct property, else `false`.
     * @example
     *
     * _.has({ 'a': 1, 'b': 2, 'c': 3 }, 'b');
     * // => true
     */
    function has(object, key) {
      return object ? hasOwnProperty.call(object, key) : false;
    }

    /**
     * Creates an object composed of the inverted keys and values of the given
     * object. If the given object contains duplicate values, subsequent values
     * overwrite property assignments of previous values unless `multiValue`
     * is `true`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to invert.
     * @param {boolean} [multiValue=false] Allow multiple values per key.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Object} Returns the new inverted object.
     * @example
     *
     * _.invert({ 'first': 'fred', 'second': 'barney' });
     * // => { 'fred': 'first', 'barney': 'second' }
     *
     * // without `multiValue`
     * _.invert({ 'first': 'fred', 'second': 'barney', 'third': 'fred' });
     * // => { 'fred': 'third', 'barney': 'second' }
     *
     * // with `multiValue`
     * _.invert({ 'first': 'fred', 'second': 'barney', 'third': 'fred' }, true);
     * // => { 'fred': ['first', 'third'], 'barney': ['second'] }
     */
    function invert(object, multiValue, guard) {
      multiValue = guard ? null : multiValue;

      var index = -1,
          props = keys(object),
          length = props.length,
          result = {};

      while (++index < length) {
        var key = props[index],
            value = object[key];

        if (multiValue) {
          if (hasOwnProperty.call(result, value)) {
            result[value].push(key);
          } else {
            result[value] = [key];
          }
        }
        else {
          result[value] = key;
        }
      }
      return result;
    }

    /**
     * Creates an array of the own enumerable property names of `object`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to inspect.
     * @returns {Array} Returns the array of property names.
     * @example
     *
     * function Shape() {
     *   this.x = 0;
     *   this.y = 0;
     * }
     *
     * Shape.prototype.z = 0;
     *
     * _.keys(new Shape);
     * // => ['x', 'y'] (iteration order is not guaranteed)
     */
    var keys = !nativeKeys ? shimKeys : function(object) {
      if (object) {
        var Ctor = object.constructor,
            length = object.length;
      }
      if ((typeof Ctor == 'function' && Ctor.prototype === object) ||
          (typeof length == 'number' && length > 0)) {
        return shimKeys(object);
      }
      return isObject(object) ? nativeKeys(object) : [];
    };

    /**
     * Creates an array of the own and inherited enumerable property names of `object`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to inspect.
     * @returns {Array} Returns the array of property names.
     * @example
     *
     * function Shape() {
     *   this.x = 0;
     *   this.y = 0;
     * }
     *
     * Shape.prototype.z = 0;
     *
     * _.keysIn(new Shape);
     * // => ['x', 'y', 'z'] (iteration order is not guaranteed)
     */
    function keysIn(object) {
      if (object == null) {
        return [];
      }
      if (!isObject(object)) {
        object = Object(object);
      }
      var length = object.length;
      length = (typeof length == 'number' && length > 0 &&
        (isArray(object) || (support.nonEnumArgs && isArguments(object))) && length) || 0;

      var keyIndex,
          Ctor = object.constructor,
          index = -1,
          isProto = typeof Ctor == 'function' && Ctor.prototype == object,
          maxIndex = length - 1,
          result = Array(length),
          skipIndexes = length > 0;

      while (++index < length) {
        result[index] = String(index);
      }
      for (var key in object) {
        if (!(isProto && key == 'constructor') &&
            !(skipIndexes && (keyIndex = +key, keyIndex > -1 && keyIndex <= maxIndex && keyIndex % 1 == 0))) {
          result.push(key);
        }
      }
      return result;
    }

    /**
     * Creates an object with the same keys as `object` and values generated by
     * running each own enumerable property of `object` through `iteratee`. The
     * iteratee function is bound to `thisArg` and invoked with three arguments;
     * (value, key, object).
     *
     * If a property name is provided for `iteratee` the created "_.pluck" style
     * callback returns the property value of the given element.
     *
     * If an object is provided for `iteratee` the created "_.where" style callback
     * returns `true` for elements that have the properties of the given object,
     * else `false`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to iterate over.
     * @param {Function|Object|string} [iteratee=identity] The function invoked
     *  per iteration. If a property name or object is provided it is used to
     *  create a "_.pluck" or "_.where" style callback respectively.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Object} Returns the new mapped object.
     * @example
     *
     * _.mapValues({ 'a': 1, 'b': 2, 'c': 3} , function(n) { return n * 3; });
     * // => { 'a': 3, 'b': 6, 'c': 9 }
     *
     * var users = {
     *   'fred': { 'user': 'fred', 'age': 40 },
     *   'pebbles': { 'user': 'pebbles', 'age': 1 }
     * };
     *
     * // using "_.pluck" callback shorthand
     * _.mapValues(users, 'age');
     * // => { 'fred': 40, 'pebbles': 1 }
     */
    function mapValues(object, iteratee, thisArg) {
      iteratee = getCallback(iteratee, thisArg, 3);

      var result = {}
      baseForOwn(object, function(value, key, object) {
        result[key] = iteratee(value, key, object);
      });
      return result;
    }

    /**
     * Recursively merges own enumerable properties of the source object(s), that
     * don't resolve to `undefined` into the destination object. Subsequent sources
     * overwrite property assignments of previous sources. If `customizer` is
     * provided it is invoked to produce the merged values of the destination and
     * source properties. If `customizer` returns `undefined` merging is handled
     * by the method instead. The `customizer` is bound to `thisArg` and invoked
     * with five arguments; (objectValue, sourceValue, key, object, source).
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The destination object.
     * @param {...Object} [sources] The source objects.
     * @param {Function} [customizer] The function to customize merging properties.
     * @param {*} [thisArg] The `this` binding of `customizer`.
     * @returns {Object} Returns the destination object.
     * @example
     *
     * var users = {
     *   'data': [{ 'user': 'barney' }, { 'user': 'fred' }]
     * };
     *
     * var ages = {
     *   'data': [{ 'age': 36 }, { 'age': 40 }]
     * };
     *
     * _.merge(users, ages);
     * // => { 'data': [{ 'user': 'barney', 'age': 36 }, { 'user': 'fred', 'age': 40 }] }
     *
     * var food = {
     *   'fruits': ['apple'],
     *   'vegetables': ['beet']
     * };
     *
     * var otherFood = {
     *   'fruits': ['banana'],
     *   'vegetables': ['carrot']
     * };
     *
     * _.merge(food, otherFood, function(a, b) {
     *   return _.isArray(a) ? a.concat(b) : undefined;
     * });
     * // => { 'fruits': ['apple', 'banana'], 'vegetables': ['beet', 'carrot] }
     */
    var merge = createAssigner(baseMerge);

    /**
     * Creates a shallow clone of `object` excluding the specified properties.
     * Property names may be specified as individual arguments or as arrays of
     * property names. If `predicate` is provided it is invoked for each property
     * of `object` omitting the properties `predicate` returns truthy for. The
     * predicate is bound to `thisArg` and invoked with three arguments;
     * (value, key, object).
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The source object.
     * @param {Function|...(string|string[])} [predicate] The function invoked per
     *  iteration or property names to omit, specified as individual property
     *  names or arrays of property names.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Object} Returns the new object.
     * @example
     *
     * _.omit({ 'user': 'fred', 'age': 40 }, 'age');
     * // => { 'user': 'fred' }
     *
     * _.omit({ 'user': 'fred', 'age': 40 }, function(value) {
     *   return typeof value == 'number';
     * });
     * // => { 'user': 'fred' }
     */
    function omit(object, predicate, thisArg) {
      if (object == null) {
        return {};
      }
      if (typeof predicate != 'function') {
        var props = arrayMap(baseFlatten(arguments, false, false, 1), String);
        return pickByArray(object, baseDifference(keysIn(object), props));
      }
      predicate = getCallback(predicate, thisArg, 3);
      return pickByCallback(object, function(value, key, object) {
        return !predicate(value, key, object);
      });
    }

    /**
     * Creates a two dimensional array of a given object's key-value pairs,
     * e.g. `[[key1, value1], [key2, value2]]`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to inspect.
     * @returns {Array} Returns the new array of key-value pairs.
     * @example
     *
     * _.pairs({ 'barney': 36, 'fred': 40 });
     * // => [['barney', 36], ['fred', 40]] (iteration order is not guaranteed)
     */
    function pairs(object) {
      var index = -1,
          props = keys(object),
          length = props.length,
          result = Array(length);

      while (++index < length) {
        var key = props[index];
        result[index] = [key, object[key]];
      }
      return result;
    }

    /**
     * Creates a shallow clone of `object` composed of the specified properties.
     * Property names may be specified as individual arguments or as arrays of
     * property names. If `predicate` is provided it is invoked for each property
     * of `object` picking the properties `predicate` returns truthy for. The
     * predicate is bound to `thisArg` and invoked with three arguments;
     * (value, key, object).
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The source object.
     * @param {Function|...(string|string[])} [predicate] The function invoked per
     *  iteration or property names to pick, specified as individual property
     *  names or arrays of property names.
     * @param {*} [thisArg] The `this` binding of `predicate`.
     * @returns {Object} Returns the new object.
     * @example
     *
     * _.pick({ 'user': 'fred', '_userid': 'fred1' }, 'user');
     * // => { 'user': 'fred' }
     *
     * _.pick({ 'user': 'fred', '_userid': 'fred1' }, function(value, key) {
     *   return key.charAt(0) != '_';
     * });
     * // => { 'user': 'fred' }
     */
    function pick(object, predicate, thisArg) {
      if (object == null) {
        return {};
      }
      return typeof predicate == 'function'
        ? pickByCallback(object, getCallback(predicate, thisArg, 3))
        : pickByArray(object, baseFlatten(arguments, false, false, 1));
    }

    /**
     * An alternative to `_.reduce`; this method transforms `object` to a new
     * `accumulator` object which is the result of running each of its own
     * enumerable properties through `iteratee`, with each invocation potentially
     * mutating the `accumulator` object. The `iteratee` is bound to `thisArg`
     * and invoked with four arguments; (accumulator, value, key, object). Iterator
     * functions may exit iteration early by explicitly returning `false`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Array|Object} object The object to iterate over.
     * @param {Function} [iteratee=identity] The function invoked per iteration.
     * @param {*} [accumulator] The custom accumulator value.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {*} Returns the accumulated value.
     * @example
     *
     * var squares = _.transform([1, 2, 3, 4, 5, 6], function(result, n) {
     *   n *= n;
     *   if (n % 2) {
     *     return result.push(n) < 3;
     *   }
     * });
     * // => [1, 9, 25]
     *
     * var mapped = _.transform({ 'a': 1, 'b': 2, 'c': 3 }, function(result, n, key) {
     *   result[key] = n * 3;
     * });
     * // => { 'a': 3, 'b': 6, 'c': 9 }
     */
    function transform(object, iteratee, accumulator, thisArg) {
      iteratee = getCallback(iteratee, thisArg, 4);

      var isArr = isArrayLike(object);
      if (accumulator == null) {
        if (isArr) {
          accumulator = [];
        } else if (isObject(object)) {
          var Ctor = object.constructor;
          accumulator = baseCreate(typeof Ctor == 'function' && Ctor.prototype);
        } else {
          accumulator = {};
        }
      }
      (isArr ? arrayEach : baseForOwn)(object, function(value, index, object) {
        return iteratee(accumulator, value, index, object);
      });
      return accumulator;
    }

    /**
     * Creates an array of the own enumerable property values of `object`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to inspect.
     * @returns {Array} Returns the array of property values.
     * @example
     *
     * function Shape(x, y) {
     *   this.x = x;
     *   this.y = y;
     * }
     *
     * Shape.prototype.z = 0;
     *
     * _.values(new Shape(2, 1));
     * // => [2, 1] (iteration order is not guaranteed)
     */
    function values(object) {
      return baseValues(object, keys);
    }

    /**
     * Creates an array of the own and inherited enumerable property values
     * of `object`.
     *
     * @static
     * @memberOf _
     * @category Object
     * @param {Object} object The object to inspect.
     * @returns {Array} Returns the array of property values.
     * @example
     *
     * function Shape(x, y) {
     *   this.x = x;
     *   this.y = y;
     * }
     *
     * Shape.prototype.z = 0;
     *
     * _.valuesIn(new Shape(2, 1));
     * // => [2, 1, 0] (iteration order is not guaranteed)
     */
    function valuesIn(object) {
      return baseValues(object, keysIn);
    }

    /*------------------------------------------------------------------------*/

    /**
     * Converts `string` to camel case.
     * See [Wikipedia](http://en.wikipedia.org/wiki/CamelCase) for more details.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to camel case.
     * @returns {string} Returns the camel cased string.
     * @example
     *
     * _.camelCase('Hello world');
     * // => 'helloWorld'
     *
     * _.camelCase('--hello-world');
     * // => 'helloWorld'
     *
     * _.camelCase('__hello_world__');
     * // => 'helloWorld'
     */
    var camelCase = createCompounder(function(result, word, index) {
      word = word.toLowerCase();
      return index ? (result + word.charAt(0).toUpperCase() + word.slice(1)) : word;
    });

    /**
     * Capitalizes the first character of `string`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to capitalize.
     * @returns {string} Returns the capitalized string.
     * @example
     *
     * _.capitalize('fred');
     * // => 'Fred'
     */
    function capitalize(string) {
      string = string == null ? '' : String(string);
      return string ? (string.charAt(0).toUpperCase() + string.slice(1)) : string;
    }

    /**
     * Deburrs `string` by converting latin-1 supplementary letters to basic latin letters.
     * See [Wikipedia](http://en.wikipedia.org/wiki/Latin-1_Supplement_(Unicode_block)#Character_table)
     * for more details.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to deburr.
     * @returns {string} Returns the beburred string.
     * @example
     *
     * _.deburr('déjà vu');
     * // => 'deja vu'
     */
    function deburr(string) {
      string = string == null ? '' : String(string);
      return string ? string.replace(reLatin1, deburrLetter) : string;
    }

    /**
     * Checks if `string` ends with a given target string.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to search.
     * @param {string} [target] The string to search for.
     * @param {number} [position=string.length] The position to search from.
     * @returns {boolean} Returns `true` if the given string ends with the
     *  target string, else `false`.
     * @example
     *
     * _.endsWith('abc', 'c');
     * // => true
     *
     * _.endsWith('abc', 'b');
     * // => false
     *
     * _.endsWith('abc', 'b', 2);
     * // => true
     */
    function endsWith(string, target, position) {
      string = string == null ? '' : String(string);
      target = String(target);

      var length = string.length;
      position = (typeof position == 'undefined' ? length : nativeMin(position < 0 ? 0 : (+position || 0), length)) - target.length;
      return position >= 0 && string.indexOf(target, position) == position;
    }

    /**
     * Converts the characters "&", "<", ">", '"', "'", and '`', in `string` to
     * their corresponding HTML entities.
     *
     * **Note:** No other characters are escaped. To escape additional characters
     * use a third-party library like [_he_](http://mths.be/he).
     *
     * When working with HTML you should always quote attribute values to reduce
     * XSS vectors. See [Ryan Grove's article](http://wonko.com/post/html-escaping)
     * for more details.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to escape.
     * @returns {string} Returns the escaped string.
     * @example
     *
     * _.escape('fred, barney, & pebbles');
     * // => 'fred, barney, &amp; pebbles'
     */
    function escape(string) {
      // reset `lastIndex` because in IE < 9 `String#replace` does not
      string = string == null ? '' : String(string);
      return string && (reUnescapedHtml.lastIndex = 0, reUnescapedHtml.test(string))
        ? string.replace(reUnescapedHtml, escapeHtmlChar)
        : string;
    }

    /**
     * Escapes the `RegExp` special characters "\", "^", "$", ".", "|", "?", "*",
     * "+", "(", ")", "[", "]", "{" and "}" in `string`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to escape.
     * @returns {string} Returns the escaped string.
     * @example
     *
     * _.escapeRegExp('[lodash](http://lodash.com/)');
     * // => '\[lodash\]\(http://lodash\.com/\)'
     */
    function escapeRegExp(string) {
      string = string == null ? '' : String(string);
      return string && (reRegExpChars.lastIndex = 0, reRegExpChars.test(string))
        ? string.replace(reRegExpChars, '\\$&')
        : string;
    }

    /**
     * Converts `string` to kebab case (a.k.a. spinal case).
     * See [Wikipedia](http://en.wikipedia.org/wiki/Letter_case#Computers) for
     * more details.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to kebab case.
     * @returns {string} Returns the kebab cased string.
     * @example
     *
     * _.kebabCase('Hello world');
     * // => 'hello-world'
     *
     * _.kebabCase('helloWorld');
     * // => 'hello-world'
     *
     * _.kebabCase('__hello_world__');
     * // => 'hello-world'
     */
    var kebabCase = createCompounder(function(result, word, index) {
      return result + (index ? '-' : '') + word.toLowerCase();
    });

    /**
     * Pads `string` on the left and right sides if it is shorter then the given
     * padding length. The `chars` string may be truncated if the number of padding
     * characters can't be evenly divided by the padding length.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to pad.
     * @param {number} [length=0] The padding length.
     * @param {string} [chars=' '] The string used as padding.
     * @returns {string} Returns the padded string.
     * @example
     *
     * _.pad('abc', 8);
     * // => '  abc   '
     *
     * _.pad('abc', 8, '_-');
     * // => '_-abc_-_'
     *
     * _.pad('abc', 3);
     * // => 'abc'
     */
    function pad(string, length, chars) {
      string = string == null ? '' : String(string);
      length = +length;

      var strLength = string.length;
      if (strLength >= length || !nativeIsFinite(length)) {
        return string;
      }
      var mid = (length - strLength) / 2,
          leftLength = floor(mid),
          rightLength = ceil(mid);

      chars = createPad('', rightLength, chars);
      return chars.slice(0, leftLength) + string + chars;
    }

    /**
     * Pads `string` on the left side if it is shorter then the given padding
     * length. The `chars` string may be truncated if the number of padding
     * characters exceeds the padding length.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to pad.
     * @param {number} [length=0] The padding length.
     * @param {string} [chars=' '] The string used as padding.
     * @returns {string} Returns the padded string.
     * @example
     *
     * _.padLeft('abc', 6);
     * // => '   abc'
     *
     * _.padLeft('abc', 6, '_-');
     * // => '_-_abc'
     *
     * _.padLeft('abc', 3);
     * // => 'abc'
     */
    function padLeft(string, length, chars) {
      string = string == null ? '' : String(string);
      return string ? (createPad(string, length, chars) + string) : string;
    }

    /**
     * Pads `string` on the right side if it is shorter then the given padding
     * length. The `chars` string may be truncated if the number of padding
     * characters exceeds the padding length.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to pad.
     * @param {number} [length=0] The padding length.
     * @param {string} [chars=' '] The string used as padding.
     * @returns {string} Returns the padded string.
     * @example
     *
     * _.padRight('abc', 6);
     * // => 'abc   '
     *
     * _.padRight('abc', 6, '_-');
     * // => 'abc_-_'
     *
     * _.padRight('abc', 3);
     * // => 'abc'
     */
    function padRight(string, length, chars) {
      string = string == null ? '' : String(string);
      return string ? (string + createPad(string, length, chars)) : string;
    }

    /**
     * Repeats the given string `n` times.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to repeat.
     * @param {number} [n=0] The number of times to repeat the string.
     * @returns {string} Returns the repeated string.
     * @example
     *
     * _.repeat('*', 3);
     * // => '***'
     *
     * _.repeat('abc', 2);
     * // => 'abcabc'
     *
     * _.repeat('abc', 0);
     * // => ''
     */
    function repeat(string, n) {
      var result = '';
      n = +n;

      if (n < 1 || string == null || !nativeIsFinite(n)) {
        return result;
      }
      string = String(string);

      // leverage the exponentiation by squaring algorithm for a faster repeat
      // http://en.wikipedia.org/wiki/Exponentiation_by_squaring
      do {
        if (n % 2) {
          result += string;
        }
        n = floor(n / 2);
        string += string;
      } while (n);

      return result;
    }

    /**
     * Converts `string` to snake case.
     * See [Wikipedia](http://en.wikipedia.org/wiki/Snake_case) for more details.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to snake case.
     * @returns {string} Returns the snake cased string.
     * @example
     *
     * _.snakeCase('Hello world');
     * // => 'hello_world'
     *
     * _.snakeCase('--hello-world');
     * // => 'hello_world'
     *
     * _.snakeCase('helloWorld');
     * // => 'hello_world'
     */
    var snakeCase = createCompounder(function(result, word, index) {
      return result + (index ? '_' : '') + word.toLowerCase();
    });

    /**
     * Checks if `string` starts with a given target string.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to search.
     * @param {string} [target] The string to search for.
     * @param {number} [position=0] The position to search from.
     * @returns {boolean} Returns `true` if the given string starts with the
     *  target string, else `false`.
     * @example
     *
     * _.startsWith('abc', 'a');
     * // => true
     *
     * _.startsWith('abc', 'b');
     * // => false
     *
     * _.startsWith('abc', 'b', 1);
     * // => true
     */
    function startsWith(string, target, position) {
      string = string == null ? '' : String(string);
      position = typeof position == 'undefined' ? 0 : nativeMin(position < 0 ? 0 : (+position || 0), string.length);
      return string.lastIndexOf(target, position) == position;
    }

    /**
     * Creates a compiled template function that can interpolate data properties
     * in "interpolate" delimiters, HTML-escape interpolated data properties in
     * "escape" delimiters, and execute JavaScript in "evaluate" delimiters. Data
     * properties may be accessed as free variables in the template. If a setting
     * object is provided it overrides `_.templateSettings` for the template.
     *
     * **Note:** In the development build `_.template` utilizes sourceURLs for easier debugging.
     * See the [HTML5 Rocks article on sourcemaps](http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/#toc-sourceurl)
     * for more details.
     *
     * For more information on precompiling templates see
     * [Lo-Dash's custom builds documentation](http://lodash.com/custom-builds).
     *
     * For more information on Chrome extension sandboxes see
     * [Chrome's extensions documentation](http://developer.chrome.com/stable/extensions/sandboxingEval.html).
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The template string.
     * @param {Object} [options] The options object.
     * @param {RegExp} [options.escape] The HTML "escape" delimiter.
     * @param {RegExp} [options.evaluate] The "evaluate" delimiter.
     * @param {Object} [options.imports] An object to import into the template as free variables.
     * @param {RegExp} [options.interpolate] The "interpolate" delimiter.
     * @param {string} [options.sourceURL] The sourceURL of the template's compiled source.
     * @param {string} [options.variable] The data object variable name.
     * @param- {Object} [otherOptions] Enables the legacy `options` param signature.
     * @returns {Function} Returns the compiled template function.
     * @example
     *
     * // using the "interpolate" delimiter to create a compiled template
     * var compiled = _.template('hello <%= user %>!');
     * compiled({ 'user': 'fred' });
     * // => 'hello fred!'
     *
     * // using the HTML "escape" delimiter to escape data property values
     * var compiled = _.template('<b><%- value %></b>');
     * compiled({ 'value': '<script>' });
     * // => '<b>&lt;script&gt;</b>'
     *
     * // using the "evaluate" delimiter to execute JavaScript and generate HTML
     * var compiled = _.template('<% _.forEach(users, function(user) { %><li><%- user %></li><% }); %>');
     * compiled({ 'users': ['fred', 'barney'] });
     * // => '<li>fred</li><li>barney</li>'
     *
     * // using the internal `print` function in "evaluate" delimiters
     * var compiled = _.template('<% print("hello " + user); %>!');
     * compiled({ 'user': 'barney' });
     * // => 'hello barney!'
     *
     * // using the ES6 delimiter as an alternative to the default "interpolate" delimiter
     * var compiled = _.template('hello ${ user }!');
     * compiled({ 'user': 'pebbles' });
     * // => 'hello pebbles!'
     *
     * // using custom template delimiters
     * _.templateSettings.interpolate = /{{([\s\S]+?)}}/g;
     * var compiled = _.template('hello {{ user }}!');
     * compiled({ 'user': 'mustache' });
     * // => 'hello mustache!'
     *
     * // using backslashes to treat delimiters as plain text
     * var compiled = _.template('<%= "\\<%- value %\\>" %>');
     * compiled({ 'value': 'ignored' });
     * // => '<%- value %>'
     *
     * // using the `imports` option to import `jQuery` as `jq`
     * var text = '<% jq.each(users, function(user) { %><li><%- user %></li><% }); %>';
     * var compiled = _.template(text, { 'imports': { 'jq': jQuery } });
     * compiled({ 'users': ['fred', 'barney'] });
     * // => '<li>fred</li><li>barney</li>'
     *
     * // using the `sourceURL` option to specify a custom sourceURL for the template
     * var compiled = _.template('hello <%= user %>!', { 'sourceURL': '/basic/greeting.jst' });
     * compiled(data);
     * // => find the source of "greeting.jst" under the Sources tab or Resources panel of the web inspector
     *
     * // using the `variable` option to ensure a with-statement isn't used in the compiled template
     * var compiled = _.template('hi <%= data.user %>!', { 'variable': 'data' });
     * compiled.source;
     * // => function(data) {
     *   var __t, __p = '';
     *   __p += 'hi ' + ((__t = ( data.user )) == null ? '' : __t) + '!';
     *   return __p;
     * }
     *
     * // using the `source` property to inline compiled templates for meaningful
     * // line numbers in error messages and a stack trace
     * fs.writeFileSync(path.join(cwd, 'jst.js'), '\
     *   var JST = {\
     *     "main": ' + _.template(mainText).source + '\
     *   };\
     * ');
     */
    function template(string, options, otherOptions) {
      // based on John Resig's `tmpl` implementation
      // http://ejohn.org/blog/javascript-micro-templating/
      // and Laura Doktorova's doT.js
      // https://github.com/olado/doT
      var settings = lodash.templateSettings;

      if (isIterateeCall(string, options, otherOptions)) {
        options = otherOptions = null;
      }
      string = String(string == null ? '' : string);
      options = assign({}, otherOptions || options, settings, assignOwnDefaults);

      var imports = assign({}, options.imports, settings.imports, assignOwnDefaults),
          importsKeys = keys(imports),
          importsValues = values(imports);

      var isEscaping,
          isEvaluating,
          index = 0,
          interpolate = options.interpolate || reNoMatch,
          source = "__p += '";

      // compile the regexp to match each delimiter
      var reDelimiters = RegExp(
        (options.escape || reNoMatch).source + '|' +
        interpolate.source + '|' +
        (interpolate === reInterpolate ? reEsTemplate : reNoMatch).source + '|' +
        (options.evaluate || reNoMatch).source + '|$'
      , 'g');

      // use a sourceURL for easier debugging
      // http://www.html5rocks.com/en/tutorials/developertools/sourcemaps/#toc-sourceurl
      var sourceURL = options.sourceURL || ('/lodash/template/source[' + (++templateCounter) + ']');
      sourceURL = sourceURL ? ('\n/*\n//# sourceURL=' + sourceURL + '\n*/') : '';

      string.replace(reDelimiters, function(match, escapeValue, interpolateValue, esTemplateValue, evaluateValue, offset) {
        interpolateValue || (interpolateValue = esTemplateValue);

        // escape characters that can't be included in string literals
        source += string.slice(index, offset).replace(reUnescapedString, escapeStringChar);

        // replace delimiters with snippets
        if (escapeValue) {
          isEscaping = true;
          source += "' +\n__e(" + escapeValue + ") +\n'";
        }
        if (evaluateValue) {
          isEvaluating = true;
          source += "';\n" + evaluateValue + ";\n__p += '";
        }
        if (interpolateValue) {
          source += "' +\n((__t = (" + interpolateValue + ")) == null ? '' : __t) +\n'";
        }
        index = offset + match.length;

        // the JS engine embedded in Adobe products requires returning the `match`
        // string in order to produce the correct `offset` value
        return match;
      });

      source += "';\n";

      // if `variable` is not specified, wrap a with-statement around the generated
      // code to add the data object to the top of the scope chain
      var variable = options.variable;
      if (!variable) {
        source = 'with (obj) {\n' + source + '\n}\n';
      }
      // cleanup code by stripping empty strings
      source = (isEvaluating ? source.replace(reEmptyStringLeading, '') : source)
        .replace(reEmptyStringMiddle, '$1')
        .replace(reEmptyStringTrailing, '$1;');

      // frame code as the function body
      source = 'function(' + (variable || 'obj') + ') {\n' +
        (variable
          ? ''
          : 'obj || (obj = {});\n'
        ) +
        "var __t, __p = ''" +
        (isEscaping
           ? ', __e = _.escape'
           : ''
        ) +
        (isEvaluating
          ? ', __j = Array.prototype.join;\n' +
            "function print() { __p += __j.call(arguments, '') }\n"
          : ';\n'
        ) +
        source +
        'return __p\n}';

      var result = attempt(function() {
        return Function(importsKeys, 'return ' + source + sourceURL).apply(undefined, importsValues);
      });

      // provide the compiled function's source by its `toString` method or
      // the `source` property as a convenience for inlining compiled templates
      result.source = source;
      if (isError(result)) {
        throw result;
      }
      return result;
    }

    /**
     * Removes leading and trailing whitespace or specified characters from `string`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to trim.
     * @param {string} [chars=whitespace] The characters to trim.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {string} Returns the trimmed string.
     * @example
     *
     * _.trim('  fred  ');
     * // => 'fred'
     *
     * _.trim('-_-fred-_-', '_-');
     * // => 'fred'
     */
    function trim(string, chars, guard) {
      string = string == null ? '' : String(string);
      if (!string) {
        return string;
      }
      if (guard || chars == null) {
        return string.slice(trimmedLeftIndex(string), trimmedRightIndex(string) + 1);
      }
      chars = String(chars);
      return string.slice(charsLeftIndex(string, chars), charsRightIndex(string, chars) + 1);
    }

    /**
     * Removes leading whitespace or specified characters from `string`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to trim.
     * @param {string} [chars=whitespace] The characters to trim.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {string} Returns the trimmed string.
     * @example
     *
     * _.trimLeft('  fred  ');
     * // => 'fred  '
     *
     * _.trimLeft('-_-fred-_-', '_-');
     * // => 'fred-_-'
     */
    function trimLeft(string, chars, guards) {
      string = string == null ? '' : String(string);
      if (!string) {
        return string;
      }
      if (guards || chars == null) {
        return string.slice(trimmedLeftIndex(string))
      }
      chars = String(chars);
      return string.slice(charsLeftIndex(string, chars));
    }

    /**
     * Removes trailing whitespace or specified characters from `string`.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to trim.
     * @param {string} [chars=whitespace] The characters to trim.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {string} Returns the trimmed string.
     * @example
     *
     * _.trimRight('  fred  ');
     * // => '  fred'
     *
     * _.trimRight('-_-fred-_-', '_-');
     * // => '-_-fred'
     */
    function trimRight(string, chars, guard) {
      string = string == null ? '' : String(string);
      if (!string) {
        return string;
      }
      if (guard || chars == null) {
        return string.slice(0, trimmedRightIndex(string) + 1)
      }
      chars = String(chars);
      return string.slice(0, charsRightIndex(string, chars) + 1);
    }

    /**
     * Truncates `string` if it is longer than the given maximum string length.
     * The last characters of the truncated string are replaced with the omission
     * string which defaults to "...".
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to truncate.
     * @param {Object|number} [options] The options object or maximum string length.
     * @param {number} [options.length=30] The maximum string length.
     * @param {string} [options.omission='...'] The string to indicate text is omitted.
     * @param {RegExp|string} [options.separator] The separator pattern to truncate to.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {string} Returns the truncated string.
     * @example
     *
     * _.trunc('hi-diddly-ho there, neighborino');
     * // => 'hi-diddly-ho there, neighbo...'
     *
     * _.trunc('hi-diddly-ho there, neighborino', 24);
     * // => 'hi-diddly-ho there, n...'
     *
     * _.trunc('hi-diddly-ho there, neighborino', { 'length': 24, 'separator': ' ' });
     * // => 'hi-diddly-ho there,...'
     *
     * _.trunc('hi-diddly-ho there, neighborino', { 'length': 24, 'separator': /,? +/ });
     * //=> 'hi-diddly-ho there...'
     *
     * _.trunc('hi-diddly-ho there, neighborino', { 'omission': ' [...]' });
     * // => 'hi-diddly-ho there, neig [...]'
     */
    function trunc(string, options, guard) {
      options = guard ? null : options;

      var length = DEFAULT_TRUNC_LENGTH,
          omission = DEFAULT_TRUNC_OMISSION;

      if (isObject(options)) {
        var separator = 'separator' in options ? options.separator : separator;
        length = 'length' in options ? +options.length || 0 : length;
        omission = 'omission' in options ? String(options.omission) : omission;
      }
      else if (options != null) {
        length = +options || 0;
      }
      string = string == null ? '' : String(string);
      if (length >= string.length) {
        return string;
      }
      var end = length - omission.length;
      if (end < 1) {
        return omission;
      }
      var result = string.slice(0, end);
      if (separator == null) {
        return result + omission;
      }
      if (isRegExp(separator)) {
        if (string.slice(end).search(separator)) {
          var match,
              newEnd,
              substring = string.slice(0, end);

          if (!separator.global) {
            separator = RegExp(separator.source, (reFlags.exec(separator) || '') + 'g');
          }
          separator.lastIndex = 0;
          while ((match = separator.exec(substring))) {
            newEnd = match.index;
          }
          result = result.slice(0, newEnd == null ? end : newEnd);
        }
      } else if (string.indexOf(separator, end) != end) {
        var index = result.lastIndexOf(separator);
        if (index > -1) {
          result = result.slice(0, index);
        }
      }
      return result + omission;
    }

    /**
     * The inverse of `_.escape`; this method converts the HTML entities
     * `&amp;`, `&lt;`, `&gt;`, `&quot;`, `&#39;`, and `&#96;` in `string` to their
     * corresponding characters.
     *
     * **Note:** No other HTML entities are unescaped. To unescape additional HTML
     * entities use a third-party library like [_he_](http://mths.be/he).
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to unescape.
     * @returns {string} Returns the unescaped string.
     * @example
     *
     * _.unescape('fred, barney, &amp; pebbles');
     * // => 'fred, barney, & pebbles'
     */
    function unescape(string) {
      string = string == null ? '' : String(string);
      return string && (reEscapedHtml.lastIndex = 0, reEscapedHtml.test(string))
        ? string.replace(reEscapedHtml, unescapeHtmlChar)
        : string;
    }

    /**
     * Splits `string` into an array of its words.
     *
     * @static
     * @memberOf _
     * @category String
     * @param {string} [string=''] The string to inspect.
     * @param {RegExp|string} [pattern] The pattern to match words.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Array} Returns the words of `string`.
     * @example
     *
     * _.words('fred, barney, & pebbles');
     * // => ['fred', 'barney', 'pebbles']
     *
     * _.words('fred, barney, & pebbles', /[^, ]+/g);
     * // => ['fred', 'barney', '&', 'pebbles']
     */
    function words(string, pattern, guard) {
      string = string != null && String(string);
      pattern = guard ? null : pattern;
      return (string && string.match(pattern || reWords)) || [];
    }

    /*------------------------------------------------------------------------*/

    /**
     * Attempts to invoke `func`, returning either the result or the caught
     * error object.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {*} func The function to attempt.
     * @returns {*} Returns the `func` result or error object.
     * @example
     *
     * // avoid throwing errors for invalid selectors
     * var elements = _.attempt(function() {
     *   return document.querySelectorAll(selector);
     * });
     *
     * if (_.isError(elements)) {
     *   elements = [];
     * }
     */
    function attempt(func) {
      try {
        return func();
      } catch(e) {
        return isError(e) ? e : Error(e);
      }
    }

    /**
     * Creates a function bound to an optional `thisArg`. If `func` is a property
     * name the created callback returns the property value for a given element.
     * If `func` is an object the created callback returns `true` for elements
     * that contain the equivalent object properties, otherwise it returns `false`.
     *
     * @static
     * @memberOf _
     * @alias iteratee
     * @category Utility
     * @param {*} [func=identity] The value to convert to a callback.
     * @param {*} [thisArg] The `this` binding of the created callback.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var users = [
     *   { 'user': 'barney', 'age': 36 },
     *   { 'user': 'fred',   'age': 40 }
     * ];
     *
     * // wrap to create custom callback shorthands
     * _.callback = _.wrap(_.callback, function(callback, func, thisArg) {
     *   var match = /^(.+?)__([gl]t)(.+)$/.exec(func);
     *   if (!match) {
     *     return callback(func, thisArg);
     *   }
     *   return function(object) {
     *     return match[2] == 'gt' ? object[match[1]] > match[3] : object[match[1]] < match[3];
     *   };
     * });
     *
     * _.filter(users, 'age__gt38');
     * // => [{ 'user': 'fred', 'age': 40 }]
     */
    function callback(func, thisArg, guard) {
      return baseCallback(func, guard ? undefined : thisArg);
    }

    /**
     * Creates a function that returns `value`.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {*} value The value to return from the new function.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var object = { 'user': 'fred' };
     * var getter = _.constant(object);
     * getter() === object;
     * // => true
     */
    function constant(value) {
      return function() {
        return value;
      };
    }

    /**
     * This method returns the first argument provided to it.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {*} value Any value.
     * @returns {*} Returns `value`.
     * @example
     *
     * var object = { 'user': 'fred' };
     * _.identity(object) === object;
     * // => true
     */
    function identity(value) {
      return value;
    }

    /**
     * Creates a "_.where" style predicate function which performs a deep comparison
     * between a given object and the `source` object, returning `true` if the given
     * object has equivalent property values, else `false`.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {Object} source The object of property values to match.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var users = [
     *   { 'user': 'fred',   'age': 40 },
     *   { 'user': 'barney', 'age': 36 }
     * ];
     *
     * var matchesAge = _.matches({ 'age': 36 });
     *
     * _.filter(users, matchesAge);
     * // => [{ 'user': 'barney', 'age': 36 }]
     *
     * _.find(users, matchesAge);
     * // => { 'user': 'barney', 'age': 36 }
     */
    function matches(source) {
      var props = keys(source),
          length = props.length;

      if (length == 1) {
        var key = props[0],
            value = source[key];

        if (isStrictComparable(value)) {
          return function(object) {
            return object != null && value === object[key] && hasOwnProperty.call(object, key);
          };
        }
      }
      var index = length,
          flags = Array(length),
          vals = Array(length);

      while (index--) {
        value = source[props[index]];
        var isStrict = isStrictComparable(value);

        flags[index] = isStrict;
        vals[index] = isStrict ? value : baseClone(value);
      }
      return function(object) {
        index = length;
        if (object == null) {
          return !index;
        }
        while (index--) {
          if (flags[index] ? vals[index] !== object[props[index]] : !hasOwnProperty.call(object, props[index])) {
            return false;
          }
        }
        index = length;
        while (index--) {
          if (flags[index] ? !hasOwnProperty.call(object, props[index]) : !baseIsEqual(vals[index], object[props[index]], null, true)) {
            return false;
          }
        }
        return true;
      };
    }

    /**
     * Adds all own enumerable function properties of a source object to the
     * destination object. If `object` is a function then methods are added to
     * its prototype as well.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {Function|Object} [object=this] object The destination object.
     * @param {Object} source The object of functions to add.
     * @param {Object} [options] The options object.
     * @param {boolean} [options.chain=true] Specify whether the functions added
     *  are chainable.
     * @returns {Function|Object} Returns `object`.
     * @example
     *
     * function vowels(string) {
     *   return _.filter(string, function(v) {
     *     return /[aeiou]/i.test(v);
     *   });
     * }
     *
     * _.mixin({ 'vowels': vowels });
     * _.vowels('fred');
     * // => ['e']
     *
     * _('fred').vowels().value();
     * // => ['e']
     *
     * _.mixin({ 'vowels': vowels }, { 'chain': false });
     * _('fred').vowels();
     * // => ['e']
     */
    function mixin(object, source, options) {
      var chain = true,
          isObj = isObject(source),
          noOpts = options == null,
          props = noOpts && isObj && keys(source),
          methodNames = props && baseFunctions(source, props);

      if ((props && props.length && !methodNames.length) || (noOpts && !isObj)) {
        if (noOpts) {
          options = source;
        }
        methodNames = false;
        source = object;
        object = this;
      }
      methodNames || (methodNames = baseFunctions(source, keys(source)));
      if (options === false) {
        chain = false;
      } else if (isObject(options) && 'chain' in options) {
        chain = options.chain;
      }
      var index = -1,
          isFunc = isFunction(object),
          length = methodNames.length;

      while (++index < length) {
        var methodName = methodNames[index];
        object[methodName] = source[methodName];
        if (isFunc) {
          object.prototype[methodName] = (function(methodName) {
            return function() {
              if (chain || this.__chain__) {
                var result = object(this.__wrapped__);
                result.__chain__ = this.__chain__;
                (result.__queue__ = baseSlice(this.__queue__)).push([methodName, object, arguments]);
                return result;
              }
              var args = [this.value()];
              push.apply(args, arguments);
              return object[methodName].apply(object, args);
            };
          }(methodName));
        }
      }
      return object;
    }

    /**
     * Reverts the `_` variable to its previous value and returns a reference to
     * the `lodash` function.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @returns {Function} Returns the `lodash` function.
     * @example
     *
     * var lodash = _.noConflict();
     */
    function noConflict() {
      context._ = oldDash;
      return this;
    }

    /**
     * A no-operation function.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @example
     *
     * var object = { 'user': 'fred' };
     * _.noop(object) === undefined;
     * // => true
     */
    function noop() {
      // no operation performed
    }

    /**
     * Gets the number of milliseconds that have elapsed since the Unix epoch
     * (1 January 1970 00:00:00 UTC).
     *
     * @static
     * @memberOf _
     * @category Utility
     * @example
     *
     * _.defer(function(stamp) { console.log(_.now() - stamp); }, _.now());
     * // => logs the number of milliseconds it took for the deferred function to be invoked
     */
    var now = nativeNow || function() {
      return new Date().getTime();
    };

    /**
     * Converts `value` to an integer of the specified radix. If `radix` is
     * `undefined` or `0`, a `radix` of `10` is used unless `value` is a hexadecimal,
     * in which case a `radix` of `16` is used.
     *
     * **Note:** This method avoids differences in native ES3 and ES5 `parseInt`
     * implementations. See the [ES5 spec](http://es5.github.io/#E) for more details.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {string} value The value to parse.
     * @param {number} [radix] The radix to interpret `value` by.
     * @param- {Object} [guard] Enables use as a callback for functions like `_.map`.
     * @returns {number} Returns the converted integer.
     * @example
     *
     * _.parseInt('08');
     * // => 8
     */
    function parseInt(value, radix, guard) {
      return nativeParseInt(value, guard ? 0 : radix);
    }
    // fallback for environments with pre-ES5 implementations
    if (nativeParseInt(whitespace + '08') != 8) {
      parseInt = function(value, radix, guard) {
        // Firefox < 21 and Opera < 15 follow ES3 for `parseInt` and
        // Chrome fails to trim leading <BOM> whitespace characters.
        // See https://code.google.com/p/v8/issues/detail?id=3109
        value = trim(value);
        radix = guard ? 0 : +radix;
        return nativeParseInt(value, radix || (reHexPrefix.test(value) ? 16 : 10));
      };
    }

    /**
     * Creates a "_.pluck" style function which returns the `key` value of a
     * given object.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {string} key The name of the property to retrieve.
     * @returns {Function} Returns the new function.
     * @example
     *
     * var users = [
     *   { 'user': 'fred',   'age': 40 },
     *   { 'user': 'barney', 'age': 36 }
     * ];
     *
     * var getName = _.property('user');
     *
     * _.map(users, getName);
     * // => ['barney', 'fred']
     *
     * _.sortBy(users, getName);
     * // => [{ 'user': 'barney', 'age': 36 }, { 'user': 'fred',   'age': 40 }]
     */
    function property(key) {
      return function(object) {
        return object == null ? undefined : object[key];
      };
    }

    /**
     * Produces a random number between `min` and `max` (inclusive). If only one
     * argument is provided a number between `0` and the given number is returned.
     * If `floating` is `true`, or either `min` or `max` are floats, a floating-point
     * number is returned instead of an integer.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {number} [min=0] The minimum possible value.
     * @param {number} [max=1] The maximum possible value.
     * @param {boolean} [floating=false] Specify returning a floating-point number.
     * @returns {number} Returns the random number.
     * @example
     *
     * _.random(0, 5);
     * // => an integer between 0 and 5
     *
     * _.random(5);
     * // => also an integer between 0 and 5
     *
     * _.random(5, true);
     * // => a floating-point number between 0 and 5
     *
     * _.random(1.2, 5.2);
     * // => a floating-point number between 1.2 and 5.2
     */
    function random(min, max, floating) {
      if (floating && isIterateeCall(min, max, floating)) {
        max = floating = null;
      }
      var noMin = min == null,
          noMax = max == null;

      if (floating == null) {
        if (noMax && typeof min == 'boolean') {
          floating = min;
          min = 1;
        }
        else if (typeof max == 'boolean') {
          floating = max;
          noMax = true;
        }
      }
      if (noMin && noMax) {
        max = 1;
        noMax = false;
      }
      min = +min || 0;
      if (noMax) {
        max = min;
        min = 0;
      } else {
        max = +max || 0;
      }
      if (floating || min % 1 || max % 1) {
        var rand = nativeRandom();
        return nativeMin(min + (rand * (max - min + parseFloat('1e-' + (String(rand).length - 1)))), max);
      }
      return baseRandom(min, max);
    }

    /**
     * Creates an array of numbers (positive and/or negative) progressing from
     * `start` up to but not including `end`. If `start` is less than `stop` a
     * zero-length range is created unless a negative `step` is specified.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {number} [start=0] The start of the range.
     * @param {number} end The end of the range.
     * @param {number} [step=1] The value to increment or decrement by.
     * @returns {Array} Returns the new array of numbers.
     * @example
     *
     * _.range(4);
     * // => [0, 1, 2, 3]
     *
     * _.range(1, 5);
     * // => [1, 2, 3, 4]
     *
     * _.range(0, 20, 5);
     * // => [0, 5, 10, 15]
     *
     * _.range(0, -4, -1);
     * // => [0, -1, -2, -3]
     *
     * _.range(1, 4, 0);
     * // => [1, 1, 1]
     *
     * _.range(0);
     * // => []
     */
    function range(start, end, step) {
      if (step && isIterateeCall(start, end, step)) {
        end = step = null;
      }
      start = +start || 0;
      step = step == null ? 1 : (+step || 0);

      if (end == null) {
        end = start;
        start = 0;
      } else {
        end = +end || 0;
      }
      // use `Array(length)` so engines like Chakra and V8 avoid slower modes
      // http://youtu.be/XAqIpGU8ZZk#t=17m25s
      var index = -1,
          length = nativeMax(ceil((end - start) / (step || 1)), 0),
          result = Array(length);

      while (++index < length) {
        result[index] = start;
        start += step;
      }
      return result;
    }

    /**
     * Resolves the value of property `key` on `object`. If `key` is a function
     * it is invoked with the `this` binding of `object` and its result returned,
     * else the property value is returned. If `object` is `null` or `undefined`
     * then `undefined` is returned. If a default value is provided it is returned
     * if the property value resolves to `undefined`.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {Object} object The object to inspect.
     * @param {string} key The name of the property to resolve.
     * @param {*} [defaultValue] The value returned if the property value
     *  resolves to `undefined`.
     * @returns {*} Returns the resolved value.
     * @example
     *
     * var object = {
     *   'user': 'fred',
     *   'age': function() {
     *     return 40;
     *   }
     * };
     *
     * _.result(object, 'user');
     * // => 'fred'
     *
     * _.result(object, 'age');
     * // => 40
     *
     * _.result(object, 'employer', 'slate');
     * // => 'slate'
     */
    function result(object, key, defaultValue) {
      var value = object == null ? undefined : object[key];
      if (typeof value == 'undefined') {
        return defaultValue;
      }
      return isFunction(value) ? object[key]() : value;
    }

    /**
     * Invokes the iteratee function `n` times, returning an array of the results
     * of each invocation. The `iteratee` is bound to `thisArg` and invoked with
     * one argument; (index).
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {number} n The number of times to invoke `iteratee`.
     * @param {Function} [iteratee=identity] The function invoked per iteration.
     * @param {*} [thisArg] The `this` binding of `iteratee`.
     * @returns {Array} Returns the array of results.
     * @example
     *
     * var diceRolls = _.times(3, _.partial(_.random, 1, 6, false));
     * // => [3, 6, 4]
     *
     * _.times(3, function(n) { mage.castSpell(n); });
     * // => invokes `mage.castSpell(n)` three times, passing `n` of `0`, `1`, and `2` respectively
     *
     * _.times(3, function(n) { this.cast(n); }, mage);
     * // => also invokes `mage.castSpell(n)` three times
     */
    function times(n, iteratee, thisArg) {
      n = nativeIsFinite(n = +n) && n > -1 ? n : 0;
      iteratee = baseCallback(iteratee, thisArg, 1);

      var index = -1,
          result = Array(nativeMin(n, MAX_ARRAY_LENGTH));

      while (++index < n) {
        if (index < MAX_ARRAY_LENGTH) {
          result[index] = iteratee(index);
        } else {
          iteratee(index);
        }
      }
      return result;
    }

    /**
     * Generates a unique ID. If `prefix` is provided the ID is appended to it.
     *
     * @static
     * @memberOf _
     * @category Utility
     * @param {string} [prefix] The value to prefix the ID with.
     * @returns {string} Returns the unique ID.
     * @example
     *
     * _.uniqueId('contact_');
     * // => 'contact_104'
     *
     * _.uniqueId();
     * // => '105'
     */
    function uniqueId(prefix) {
      var id = ++idCounter;
      return String(prefix == null ? '' : prefix) + id;
    }

    /*------------------------------------------------------------------------*/

    // add functions that return wrapped values when chaining
    lodash.after = after;
    lodash.assign = assign;
    lodash.at = at;
    lodash.before = before;
    lodash.bind = bind;
    lodash.bindAll = bindAll;
    lodash.bindKey = bindKey;
    lodash.callback = callback;
    lodash.chain = chain;
    lodash.chunk = chunk;
    lodash.compact = compact;
    lodash.constant = constant;
    lodash.countBy = countBy;
    lodash.create = create;
    lodash.curry = curry;
    lodash.curryRight = curryRight;
    lodash.debounce = debounce;
    lodash.defaults = defaults;
    lodash.defer = defer;
    lodash.delay = delay;
    lodash.difference = difference;
    lodash.drop = drop;
    lodash.dropRight = dropRight;
    lodash.dropRightWhile = dropRightWhile;
    lodash.dropWhile = dropWhile;
    lodash.filter = filter;
    lodash.flatten = flatten;
    lodash.flattenDeep = flattenDeep;
    lodash.flow = flow;
    lodash.flowRight = flowRight;
    lodash.forEach = forEach;
    lodash.forEachRight = forEachRight;
    lodash.forIn = forIn;
    lodash.forInRight = forInRight;
    lodash.forOwn = forOwn;
    lodash.forOwnRight = forOwnRight;
    lodash.functions = functions;
    lodash.groupBy = groupBy;
    lodash.indexBy = indexBy;
    lodash.initial = initial;
    lodash.intersection = intersection;
    lodash.invert = invert;
    lodash.invoke = invoke;
    lodash.keys = keys;
    lodash.keysIn = keysIn;
    lodash.map = map;
    lodash.mapValues = mapValues;
    lodash.matches = matches;
    lodash.memoize = memoize;
    lodash.merge = merge;
    lodash.mixin = mixin;
    lodash.negate = negate;
    lodash.omit = omit;
    lodash.once = once;
    lodash.pairs = pairs;
    lodash.partial = partial;
    lodash.partialRight = partialRight;
    lodash.partition = partition;
    lodash.pick = pick;
    lodash.pluck = pluck;
    lodash.property = property;
    lodash.pull = pull;
    lodash.pullAt = pullAt;
    lodash.range = range;
    lodash.reject = reject;
    lodash.remove = remove;
    lodash.rest = rest;
    lodash.shuffle = shuffle;
    lodash.slice = slice;
    lodash.sortBy = sortBy;
    lodash.take = take;
    lodash.takeRight = takeRight;
    lodash.takeRightWhile = takeRightWhile;
    lodash.takeWhile = takeWhile;
    lodash.tap = tap;
    lodash.throttle = throttle;
    lodash.thru = thru;
    lodash.times = times;
    lodash.toArray = toArray;
    lodash.transform = transform;
    lodash.union = union;
    lodash.uniq = uniq;
    lodash.unzip = unzip;
    lodash.values = values;
    lodash.valuesIn = valuesIn;
    lodash.where = where;
    lodash.without = without;
    lodash.wrap = wrap;
    lodash.xor = xor;
    lodash.zip = zip;
    lodash.zipObject = zipObject;

    // add aliases
    lodash.backflow = flowRight;
    lodash.collect = map;
    lodash.compose = flowRight;
    lodash.each = forEach;
    lodash.eachRight = forEachRight;
    lodash.extend = assign;
    lodash.iteratee = callback;
    lodash.methods = functions;
    lodash.object = zipObject;
    lodash.select = filter;
    lodash.tail = rest;
    lodash.unique = uniq;

    // add functions to `lodash.prototype`
    mixin(lodash, lodash);

    /*------------------------------------------------------------------------*/

    // add functions that return unwrapped values when chaining
    lodash.attempt = attempt;
    lodash.camelCase = camelCase;
    lodash.capitalize = capitalize;
    lodash.clone = clone;
    lodash.cloneDeep = cloneDeep;
    lodash.contains = contains;
    lodash.deburr = deburr;
    lodash.endsWith = endsWith;
    lodash.escape = escape;
    lodash.escapeRegExp = escapeRegExp;
    lodash.every = every;
    lodash.find = find;
    lodash.findIndex = findIndex;
    lodash.findKey = findKey;
    lodash.findLast = findLast;
    lodash.findLastIndex = findLastIndex;
    lodash.findLastKey = findLastKey;
    lodash.findWhere = findWhere;
    lodash.first = first;
    lodash.has = has;
    lodash.identity = identity;
    lodash.indexOf = indexOf;
    lodash.isArguments = isArguments;
    lodash.isArray = isArray;
    lodash.isBoolean = isBoolean;
    lodash.isDate = isDate;
    lodash.isElement = isElement;
    lodash.isEmpty = isEmpty;
    lodash.isEqual = isEqual;
    lodash.isError = isError;
    lodash.isFinite = isFinite;
    lodash.isFunction = isFunction;
    lodash.isNaN = isNaN;
    lodash.isNative = isNative;
    lodash.isNull = isNull;
    lodash.isNumber = isNumber;
    lodash.isObject = isObject;
    lodash.isPlainObject = isPlainObject;
    lodash.isRegExp = isRegExp;
    lodash.isString = isString;
    lodash.isUndefined = isUndefined;
    lodash.kebabCase = kebabCase;
    lodash.last = last;
    lodash.lastIndexOf = lastIndexOf;
    lodash.max = max;
    lodash.min = min;
    lodash.noConflict = noConflict;
    lodash.noop = noop;
    lodash.now = now;
    lodash.pad = pad;
    lodash.padLeft = padLeft;
    lodash.padRight = padRight;
    lodash.parseInt = parseInt;
    lodash.random = random;
    lodash.reduce = reduce;
    lodash.reduceRight = reduceRight;
    lodash.repeat = repeat;
    lodash.result = result;
    lodash.runInContext = runInContext;
    lodash.size = size;
    lodash.snakeCase = snakeCase;
    lodash.some = some;
    lodash.sortedIndex = sortedIndex;
    lodash.sortedLastIndex = sortedLastIndex;
    lodash.startsWith = startsWith;
    lodash.template = template;
    lodash.trim = trim;
    lodash.trimLeft = trimLeft;
    lodash.trimRight = trimRight;
    lodash.trunc = trunc;
    lodash.unescape = unescape;
    lodash.uniqueId = uniqueId;
    lodash.words = words;

    // add aliases
    lodash.all = every;
    lodash.any = some;
    lodash.detect = find;
    lodash.foldl = reduce;
    lodash.foldr = reduceRight;
    lodash.head = first;
    lodash.include = contains;
    lodash.inject = reduce;

    mixin(lodash, (function() {
      var source = {};
      baseForOwn(lodash, function(func, methodName) {
        if (!lodash.prototype[methodName]) {
          source[methodName] = func;
        }
      });
      return source;
    }()), false);

    /*------------------------------------------------------------------------*/

    // add functions capable of returning wrapped and unwrapped values when chaining
    lodash.sample = sample;

    lodash.prototype.sample = function(n, guard) {
      n = guard ? null : n;
      if (!this.__chain__ && n == null) {
        return lodash.sample(this.value());
      }
      return this.thru(function(value) {
        return lodash.sample(value, n);
      });
    };

    /*------------------------------------------------------------------------*/

    /**
     * The semantic version number.
     *
     * @static
     * @memberOf _
     * @type string
     */
    lodash.VERSION = VERSION;

    // ensure `new lodashWrapper` is an instance of `lodash`
    lodashWrapper.prototype = lodash.prototype;

    // add "Chaining" functions to the wrapper
    lodash.prototype.chain = wrapperChain;
    lodash.prototype.toString = wrapperToString;
    lodash.prototype.toJSON = lodash.prototype.value = lodash.prototype.valueOf = wrapperValueOf;

    // assign default placeholders
    arrayEach(['bind', 'bindKey', 'curry', 'curryRight', 'partial', 'partialRight'], function(methodName) {
      lodash[methodName].placeholder = lodash;
    });

    // add `Array.prototype` functions
    arrayEach(['concat', 'join', 'pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(methodName) {
      var func = arrayProto[methodName],
          retUnwrapped = /^(?:join|pop|shift)$/.test(methodName),
          chainName = /^(?:push|reverse|sort|unshift)$/.test(methodName) ? 'tap' : 'thru';

      lodash.prototype[methodName] = function() {
        var args = arguments;
        if (retUnwrapped && !this.__chain__) {
          return func.apply(this.value(), args);
        }
        return this[chainName](function(value) {
          return func.apply(value, args);
        });
      };
    });

    return lodash;
  }

  /*--------------------------------------------------------------------------*/

  // export Lo-Dash
  var _ = runInContext();

  // some AMD build optimizers like r.js check for condition patterns like the following:
  if (typeof define == 'function' && typeof define.amd == 'object' && define.amd) {
    // Expose Lo-Dash to the global object when an AMD loader is present to avoid
    // errors in cases where Lo-Dash is loaded by a script tag and not intended
    // as an AMD module. See http://requirejs.org/docs/errors.html#mismatch
    root._ = _;

    // define as an anonymous module so, through path mapping, it can be
    // referenced as the "underscore" module
    define(function() {
      return _;
    });
  }
  // check for `exports` after `define` in case a build optimizer adds an `exports` object
  else if (freeExports && freeModule) {
    // in Node.js or RingoJS
    if (moduleExports) {
      (freeModule.exports = _)._ = _;
    }
    // in Narwhal or Rhino -require
    else {
      freeExports._ = _;
    }
  }
  else {
    // in a browser or Rhino
    root._ = _;
  }
}.call(this));