underscore.js

//     Underscore.js 1.2.1
//     (c) 2011 Jeremy Ashkenas, DocumentCloud Inc.
//     Underscore is freely distributable under the MIT license.
//     Portions of Underscore are inspired or borrowed from Prototype,
//     Oliver Steele's Functional, and John Resig's Micro-Templating.
//     For all details and documentation:
//     http://documentcloud.github.com/underscore

// Also I added the underscore string helpers to this as a single file.

(function() {

  // Baseline setup
  // --------------

  // Establish the root object, `window` in the browser, or `global` on the server.
  var root = this;

  // Save the previous value of the `_` variable.
  var previousUnderscore = root._;

  // Establish the object that gets returned to break out of a loop iteration.
  var breaker = {};

  // Save bytes in the minified (but not gzipped) version:
  var ArrayProto = Array.prototype, ObjProto = Object.prototype, FuncProto = Function.prototype;

  // Create quick reference variables for speed access to core prototypes.
  var slice            = ArrayProto.slice,
      unshift          = ArrayProto.unshift,
      toString         = ObjProto.toString,
      hasOwnProperty   = ObjProto.hasOwnProperty;

  // All **ECMAScript 5** native function implementations that we hope to use
  // are declared here.
  var
    nativeForEach      = ArrayProto.forEach,
    nativeMap          = ArrayProto.map,
    nativeReduce       = ArrayProto.reduce,
    nativeReduceRight  = ArrayProto.reduceRight,
    nativeFilter       = ArrayProto.filter,
    nativeEvery        = ArrayProto.every,
    nativeSome         = ArrayProto.some,
    nativeIndexOf      = ArrayProto.indexOf,
    nativeLastIndexOf  = ArrayProto.lastIndexOf,
    nativeIsArray      = Array.isArray,
    nativeKeys         = Object.keys,
    nativeBind         = FuncProto.bind;

  // Create a safe reference to the Underscore object for use below.
  var _ = function(obj) { return new wrapper(obj); };

  // Current version.
  _.VERSION = '1.2.1';

  // Collection Functions
  // --------------------

  // The cornerstone, an `each` implementation, aka `forEach`.
  // Handles objects with the built-in `forEach`, arrays, and raw objects.
  // Delegates to **ECMAScript 5**'s native `forEach` if available.
  var each = _.each = _.forEach = function(obj, iterator, context) {
    if (obj == null) return;
    if (nativeForEach && obj.forEach === nativeForEach) {
      obj.forEach(iterator, context);
    } else if (obj.length === +obj.length) {
      for (var i = 0, l = obj.length; i < l; i++) {
        if (i in obj && iterator.call(context, obj[i], i, obj) === breaker) return;
      }
    } else {
      for (var key in obj) {
        if (hasOwnProperty.call(obj, key)) {
          if (iterator.call(context, obj[key], key, obj) === breaker) return;
        }
      }
    }
  };

  // Return the results of applying the iterator to each element.
  // Delegates to **ECMAScript 5**'s native `map` if available.
  _.map = function(obj, iterator, context) {
    var results = [];
    if (obj == null) return results;
    if (nativeMap && obj.map === nativeMap) return obj.map(iterator, context);
    each(obj, function(value, index, list) {
      results[results.length] = iterator.call(context, value, index, list);
    });
    return results;
  };

  // **Reduce** builds up a single result from a list of values, aka `inject`,
  // or `foldl`. Delegates to **ECMAScript 5**'s native `reduce` if available.
  _.reduce = _.foldl = _.inject = function(obj, iterator, memo, context) {
    var initial = memo !== void 0;
    if (obj == null) obj = [];
    if (nativeReduce && obj.reduce === nativeReduce) {
      if (context) iterator = _.bind(iterator, context);
      return initial ? obj.reduce(iterator, memo) : obj.reduce(iterator);
    }
    each(obj, function(value, index, list) {
      if (!initial) {
        memo = value;
        initial = true;
      } else {
        memo = iterator.call(context, memo, value, index, list);
      }
    });
    if (!initial) throw new TypeError("Reduce of empty array with no initial value");
    return memo;
  };

  // The right-associative version of reduce, also known as `foldr`.
  // Delegates to **ECMAScript 5**'s native `reduceRight` if available.
  _.reduceRight = _.foldr = function(obj, iterator, memo, context) {
    if (obj == null) obj = [];
    if (nativeReduceRight && obj.reduceRight === nativeReduceRight) {
      if (context) iterator = _.bind(iterator, context);
      return memo !== void 0 ? obj.reduceRight(iterator, memo) : obj.reduceRight(iterator);
    }
    var reversed = (_.isArray(obj) ? obj.slice() : _.toArray(obj)).reverse();
    return _.reduce(reversed, iterator, memo, context);
  };

  // Return the first value which passes a truth test. Aliased as `detect`.
  _.find = _.detect = function(obj, iterator, context) {
    var result;
    any(obj, function(value, index, list) {
      if (iterator.call(context, value, index, list)) {
        result = value;
        return true;
      }
    });
    return result;
  };

  // Return all the elements that pass a truth test.
  // Delegates to **ECMAScript 5**'s native `filter` if available.
  // Aliased as `select`.
  _.filter = _.select = function(obj, iterator, context) {
    var results = [];
    if (obj == null) return results;
    if (nativeFilter && obj.filter === nativeFilter) return obj.filter(iterator, context);
    each(obj, function(value, index, list) {
      if (iterator.call(context, value, index, list)) results[results.length] = value;
    });
    return results;
  };

  // Return all the elements for which a truth test fails.
  _.reject = function(obj, iterator, context) {
    var results = [];
    if (obj == null) return results;
    each(obj, function(value, index, list) {
      if (!iterator.call(context, value, index, list)) results[results.length] = value;
    });
    return results;
  };

  // Determine whether all of the elements match a truth test.
  // Delegates to **ECMAScript 5**'s native `every` if available.
  // Aliased as `all`.
  _.every = _.all = function(obj, iterator, context) {
    var result = true;
    if (obj == null) return result;
    if (nativeEvery && obj.every === nativeEvery) return obj.every(iterator, context);
    each(obj, function(value, index, list) {
      if (!(result = result && iterator.call(context, value, index, list))) return breaker;
    });
    return result;
  };

  // Determine if at least one element in the object matches a truth test.
  // Delegates to **ECMAScript 5**'s native `some` if available.
  // Aliased as `any`.
  var any = _.some = _.any = function(obj, iterator, context) {
    iterator = iterator || _.identity;
    var result = false;
    if (obj == null) return result;
    if (nativeSome && obj.some === nativeSome) return obj.some(iterator, context);
    each(obj, function(value, index, list) {
      if (result |= iterator.call(context, value, index, list)) return breaker;
    });
    return !!result;
  };

  // Determine if a given value is included in the array or object using `===`.
  // Aliased as `contains`.
  _.include = _.contains = function(obj, target) {
    var found = false;
    if (obj == null) return found;
    if (nativeIndexOf && obj.indexOf === nativeIndexOf) return obj.indexOf(target) != -1;
    found = any(obj, function(value) {
      if (value === target) return true;
    });
    return found;
  };

  // Invoke a method (with arguments) on every item in a collection.
  _.invoke = function(obj, method) {
    var args = slice.call(arguments, 2);
    return _.map(obj, function(value) {
      return (method.call ? method || value : value[method]).apply(value, args);
    });
  };

  // Convenience version of a common use case of `map`: fetching a property.
  _.pluck = function(obj, key) {
    return _.map(obj, function(value){ return value[key]; });
  };

  // Return the maximum element or (element-based computation).
  _.max = function(obj, iterator, context) {
    if (!iterator && _.isArray(obj)) return Math.max.apply(Math, obj);
    if (!iterator && _.isEmpty(obj)) return -Infinity;
    var result = {computed : -Infinity};
    each(obj, function(value, index, list) {
      var computed = iterator ? iterator.call(context, value, index, list) : value;
      computed >= result.computed && (result = {value : value, computed : computed});
    });
    return result.value;
  };

  // Return the minimum element (or element-based computation).
  _.min = function(obj, iterator, context) {
    if (!iterator && _.isArray(obj)) return Math.min.apply(Math, obj);
    if (!iterator && _.isEmpty(obj)) return Infinity;
    var result = {computed : Infinity};
    each(obj, function(value, index, list) {
      var computed = iterator ? iterator.call(context, value, index, list) : value;
      computed < result.computed && (result = {value : value, computed : computed});
    });
    return result.value;
  };

  // Shuffle an array.
  _.shuffle = function(obj) {
    var shuffled = [], rand;
    each(obj, function(value, index, list) {
      if (index == 0) {
        shuffled[0] = value;
      } else {
        rand = Math.floor(Math.random() * (index + 1));
        shuffled[index] = shuffled[rand];
        shuffled[rand] = value;
      }
    });
    return shuffled;
  };

  // Sort the object's values by a criterion produced by an iterator.
  _.sortBy = function(obj, iterator, context) {
    return _.pluck(_.map(obj, function(value, index, list) {
      return {
        value : value,
        criteria : iterator.call(context, value, index, list)
      };
    }).sort(function(left, right) {
      var a = left.criteria, b = right.criteria;
      return a < b ? -1 : a > b ? 1 : 0;
    }), 'value');
  };

  // Groups the object's values by a criterion. Pass either a string attribute
  // to group by, or a function that returns the criterion.
  _.groupBy = function(obj, val) {
    var result = {};
    var iterator = _.isFunction(val) ? val : function(obj) { return obj[val]; };
    each(obj, function(value, index) {
      var key = iterator(value, index);
      (result[key] || (result[key] = [])).push(value);
    });
    return result;
  };

  // Use a comparator function to figure out at what index an object should
  // be inserted so as to maintain order. Uses binary search.
  _.sortedIndex = function(array, obj, iterator) {
    iterator || (iterator = _.identity);
    var low = 0, high = array.length;
    while (low < high) {
      var mid = (low + high) >> 1;
      iterator(array[mid]) < iterator(obj) ? low = mid + 1 : high = mid;
    }
    return low;
  };

  // Safely convert anything iterable into a real, live array.
  _.toArray = function(iterable) {
    if (!iterable)                return [];
    if (iterable.toArray)         return iterable.toArray();
    if (_.isArray(iterable))      return slice.call(iterable);
    if (_.isArguments(iterable))  return slice.call(iterable);
    return _.values(iterable);
  };

  // Return the number of elements in an object.
  _.size = function(obj) {
    return _.toArray(obj).length;
  };

  // Array Functions
  // ---------------

  // Get the first element of an array. Passing **n** will return the first N
  // values in the array. Aliased as `head`. The **guard** check allows it to work
  // with `_.map`.
  _.first = _.head = function(array, n, guard) {
    return (n != null) && !guard ? slice.call(array, 0, n) : array[0];
  };

  // Returns everything but the last entry of the array. Especcialy useful on
  // the arguments object. Passing **n** will return all the values in
  // the array, excluding the last N. The **guard** check allows it to work with
  // `_.map`.
  _.initial = function(array, n, guard) {
    return slice.call(array, 0, array.length - ((n == null) || guard ? 1 : n));
  };

  // Get the last element of an array. Passing **n** will return the last N
  // values in the array. The **guard** check allows it to work with `_.map`.
  _.last = function(array, n, guard) {
    return (n != null) && !guard ? slice.call(array, array.length - n) : array[array.length - 1];
  };

  // Returns everything but the first entry of the array. Aliased as `tail`.
  // Especially useful on the arguments object. Passing an **index** will return
  // the rest of the values in the array from that index onward. The **guard**
  // check allows it to work with `_.map`.
  _.rest = _.tail = function(array, index, guard) {
    return slice.call(array, (index == null) || guard ? 1 : index);
  };

  // Trim out all falsy values from an array.
  _.compact = function(array) {
    return _.filter(array, function(value){ return !!value; });
  };

  // Return a completely flattened version of an array.
  _.flatten = function(array, shallow) {
    return _.reduce(array, function(memo, value) {
      if (_.isArray(value)) return memo.concat(shallow ? value : _.flatten(value));
      memo[memo.length] = value;
      return memo;
    }, []);
  };

  // Return a version of the array that does not contain the specified value(s).
  _.without = function(array) {
    return _.difference(array, slice.call(arguments, 1));
  };

  // Produce a duplicate-free version of the array. If the array has already
  // been sorted, you have the option of using a faster algorithm.
  // Aliased as `unique`.
  _.uniq = _.unique = function(array, isSorted, iterator) {
    var initial = iterator ? _.map(array, iterator) : array;
    var result = [];
    _.reduce(initial, function(memo, el, i) {
      if (0 == i || (isSorted === true ? _.last(memo) != el : !_.include(memo, el))) {
        memo[memo.length] = el;
        result[result.length] = array[i];
      }
      return memo;
    }, []);
    return result;
  };

  // Produce an array that contains the union: each distinct element from all of
  // the passed-in arrays.
  _.union = function() {
    return _.uniq(_.flatten(arguments, true));
  };

  // Produce an array that contains every item shared between all the
  // passed-in arrays. (Aliased as "intersect" for back-compat.)
  _.intersection = _.intersect = function(array) {
    var rest = slice.call(arguments, 1);
    return _.filter(_.uniq(array), function(item) {
      return _.every(rest, function(other) {
        return _.indexOf(other, item) >= 0;
      });
    });
  };

  // Take the difference between one array and another.
  // Only the elements present in just the first array will remain.
  _.difference = function(array, other) {
    return _.filter(array, function(value){ return !_.include(other, value); });
  };

  // Zip together multiple lists into a single array -- elements that share
  // an index go together.
  _.zip = function() {
    var args = slice.call(arguments);
    var length = _.max(_.pluck(args, 'length'));
    var results = new Array(length);
    for (var i = 0; i < length; i++) results[i] = _.pluck(args, "" + i);
    return results;
  };

  // If the browser doesn't supply us with indexOf (I'm looking at you, **MSIE**),
  // we need this function. Return the position of the first occurrence of an
  // item in an array, or -1 if the item is not included in the array.
  // Delegates to **ECMAScript 5**'s native `indexOf` if available.
  // If the array is large and already in sort order, pass `true`
  // for **isSorted** to use binary search.
  _.indexOf = function(array, item, isSorted) {
    if (array == null) return -1;
    var i, l;
    if (isSorted) {
      i = _.sortedIndex(array, item);
      return array[i] === item ? i : -1;
    }
    if (nativeIndexOf && array.indexOf === nativeIndexOf) return array.indexOf(item);
    for (i = 0, l = array.length; i < l; i++) if (array[i] === item) return i;
    return -1;
  };

  // Delegates to **ECMAScript 5**'s native `lastIndexOf` if available.
  _.lastIndexOf = function(array, item) {
    if (array == null) return -1;
    if (nativeLastIndexOf && array.lastIndexOf === nativeLastIndexOf) return array.lastIndexOf(item);
    var i = array.length;
    while (i--) if (array[i] === item) return i;
    return -1;
  };

  // Generate an integer Array containing an arithmetic progression. A port of
  // the native Python `range()` function. See
  // [the Python documentation](http://docs.python.org/library/functions.html#range).
  _.range = function(start, stop, step) {
    if (arguments.length <= 1) {
      stop = start || 0;
      start = 0;
    }
    step = arguments[2] || 1;

    var len = Math.max(Math.ceil((stop - start) / step), 0);
    var idx = 0;
    var range = new Array(len);

    while(idx < len) {
      range[idx++] = start;
      start += step;
    }

    return range;
  };

  // Function (ahem) Functions
  // ------------------

  // Reusable constructor function for prototype setting.
  var ctor = function(){};

  // Create a function bound to a given object (assigning `this`, and arguments,
  // optionally). Binding with arguments is also known as `curry`.
  // Delegates to **ECMAScript 5**'s native `Function.bind` if available.
  // We check for `func.bind` first, to fail fast when `func` is undefined.
  _.bind = function bind(func, context) {
    var bound, args;
    if (func.bind === nativeBind && nativeBind) return nativeBind.apply(func, slice.call(arguments, 1));
    if (!_.isFunction(func)) throw new TypeError;
    args = slice.call(arguments, 2);
    return bound = function() {
      if (!(this instanceof bound)) return func.apply(context, args.concat(slice.call(arguments)));
      ctor.prototype = func.prototype;
      var self = new ctor;
      var result = func.apply(self, args.concat(slice.call(arguments)));
      if (Object(result) === result) return result;
      return self;
    };
  };

  // Bind all of an object's methods to that object. Useful for ensuring that
  // all callbacks defined on an object belong to it.
  _.bindAll = function(obj) {
    var funcs = slice.call(arguments, 1);
    if (funcs.length == 0) funcs = _.functions(obj);
    each(funcs, function(f) { obj[f] = _.bind(obj[f], obj); });
    return obj;
  };

  // Memoize an expensive function by storing its results.
  _.memoize = function(func, hasher) {
    var memo = {};
    hasher || (hasher = _.identity);
    return function() {
      var key = hasher.apply(this, arguments);
      return hasOwnProperty.call(memo, key) ? memo[key] : (memo[key] = func.apply(this, arguments));
    };
  };

  // Delays a function for the given number of milliseconds, and then calls
  // it with the arguments supplied.
  _.delay = function(func, wait) {
    var args = slice.call(arguments, 2);
    return setTimeout(function(){ return func.apply(func, args); }, wait);
  };

  // Defers a function, scheduling it to run after the current call stack has
  // cleared.
  _.defer = function(func) {
    return _.delay.apply(_, [func, 1].concat(slice.call(arguments, 1)));
  };

  // Returns a function, that, when invoked, will only be triggered at most once
  // during a given window of time.
  _.throttle = function(func, wait) {
    var timeout, context, args, throttling, finishThrottle;
    finishThrottle = _.debounce(function(){ throttling = false; }, wait);
    return function() {
      context = this; args = arguments;
      var throttler = function() {
        timeout = null;
        func.apply(context, args);
        finishThrottle();
      };
      if (!timeout) timeout = setTimeout(throttler, wait);
      if (!throttling) func.apply(context, args);
      if (finishThrottle) finishThrottle();
      throttling = true;
    };
  };

  // Returns a function, that, as long as it continues to be invoked, will not
  // be triggered. The function will be called after it stops being called for
  // N milliseconds.
  _.debounce = function(func, wait) {
    var timeout;
    return function() {
      var context = this, args = arguments;
      var throttler = function() {
        timeout = null;
        func.apply(context, args);
      };
      clearTimeout(timeout);
      timeout = setTimeout(throttler, wait);
    };
  };

  // Returns a function that will be executed at most one time, no matter how
  // often you call it. Useful for lazy initialization.
  _.once = function(func) {
    var ran = false, memo;
    return function() {
      if (ran) return memo;
      ran = true;
      return memo = func.apply(this, arguments);
    };
  };

  // Returns the first function passed as an argument to the second,
  // allowing you to adjust arguments, run code before and after, and
  // conditionally execute the original function.
  _.wrap = function(func, wrapper) {
    return function() {
      var args = [func].concat(slice.call(arguments));
      return wrapper.apply(this, args);
    };
  };

  // Returns a function that is the composition of a list of functions, each
  // consuming the return value of the function that follows.
  _.compose = function() {
    var funcs = slice.call(arguments);
    return function() {
      var args = slice.call(arguments);
      for (var i = funcs.length - 1; i >= 0; i--) {
        args = [funcs[i].apply(this, args)];
      }
      return args[0];
    };
  };

  // Returns a function that will only be executed after being called N times.
  _.after = function(times, func) {
    return function() {
      if (--times < 1) { return func.apply(this, arguments); }
    };
  };

  // Object Functions
  // ----------------

  // Retrieve the names of an object's properties.
  // Delegates to **ECMAScript 5**'s native `Object.keys`
  _.keys = nativeKeys || function(obj) {
    if (obj !== Object(obj)) throw new TypeError('Invalid object');
    var keys = [];
    for (var key in obj) if (hasOwnProperty.call(obj, key)) keys[keys.length] = key;
    return keys;
  };

  // Retrieve the values of an object's properties.
  _.values = function(obj) {
    return _.map(obj, _.identity);
  };

  // Return a sorted list of the function names available on the object.
  // Aliased as `methods`
  _.functions = _.methods = function(obj) {
    var names = [];
    for (var key in obj) {
      if (_.isFunction(obj[key])) names.push(key);
    }
    return names.sort();
  };

  // Extend a given object with all the properties in passed-in object(s).
  _.extend = function(obj) {
    each(slice.call(arguments, 1), function(source) {
      for (var prop in source) {
        if (source[prop] !== void 0) obj[prop] = source[prop];
      }
    });
    return obj;
  };

  // Fill in a given object with default properties.
  _.defaults = function(obj) {
    each(slice.call(arguments, 1), function(source) {
      for (var prop in source) {
        if (obj[prop] == null) obj[prop] = source[prop];
      }
    });
    return obj;
  };

  // Create a (shallow-cloned) duplicate of an object.
  _.clone = function(obj) {
    if (!_.isObject(obj)) return obj;
    return _.isArray(obj) ? obj.slice() : _.extend({}, obj);
  };

  // Invokes interceptor with the obj, and then returns obj.
  // The primary purpose of this method is to "tap into" a method chain, in
  // order to perform operations on intermediate results within the chain.
  _.tap = function(obj, interceptor) {
    interceptor(obj);
    return obj;
  };

  // Internal recursive comparison function.
  function eq(a, b, stack) {
    // Identical objects are equal. `0 === -0`, but they aren't identical.
    // See the Harmony `egal` proposal: http://wiki.ecmascript.org/doku.php?id=harmony:egal.
    if (a === b) return a !== 0 || 1 / a == 1 / b;
    // A strict comparison is necessary because `null == undefined`.
    if ((a == null) || (b == null)) return a === b;
    // Unwrap any wrapped objects.
    if (a._chain) a = a._wrapped;
    if (b._chain) b = b._wrapped;
    // Invoke a custom `isEqual` method if one is provided.
    if (_.isFunction(a.isEqual)) return a.isEqual(b);
    if (_.isFunction(b.isEqual)) return b.isEqual(a);
    // Compare object types.
    var typeA = typeof a;
    if (typeA != typeof b) return false;
    // Optimization; ensure that both values are truthy or falsy.
    if (!a != !b) return false;
    // `NaN` values are equal.
    if (_.isNaN(a)) return _.isNaN(b);
    // Compare string objects by value.
    var isStringA = _.isString(a), isStringB = _.isString(b);
    if (isStringA || isStringB) return isStringA && isStringB && String(a) == String(b);
    // Compare number objects by value.
    var isNumberA = _.isNumber(a), isNumberB = _.isNumber(b);
    if (isNumberA || isNumberB) return isNumberA && isNumberB && +a == +b;
    // Compare boolean objects by value. The value of `true` is 1; the value of `false` is 0.
    var isBooleanA = _.isBoolean(a), isBooleanB = _.isBoolean(b);
    if (isBooleanA || isBooleanB) return isBooleanA && isBooleanB && +a == +b;
    // Compare dates by their millisecond values.
    var isDateA = _.isDate(a), isDateB = _.isDate(b);
    if (isDateA || isDateB) return isDateA && isDateB && a.getTime() == b.getTime();
    // Compare RegExps by their source patterns and flags.
    var isRegExpA = _.isRegExp(a), isRegExpB = _.isRegExp(b);
    if (isRegExpA || isRegExpB) {
      // Ensure commutative equality for RegExps.
      return isRegExpA && isRegExpB &&
             a.source == b.source &&
             a.global == b.global &&
             a.multiline == b.multiline &&
             a.ignoreCase == b.ignoreCase;
    }
    // Ensure that both values are objects.
    if (typeA != 'object') return false;
    // Arrays or Arraylikes with different lengths are not equal.
    if (a.length !== b.length) return false;
    // Objects with different constructors are not equal.
    if (a.constructor !== b.constructor) return false;
    // Assume equality for cyclic structures. The algorithm for detecting cyclic
    // structures is adapted from ES 5.1 section 15.12.3, abstract operation `JO`.
    var length = stack.length;
    while (length--) {
      // Linear search. Performance is inversely proportional to the number of
      // unique nested structures.
      if (stack[length] == a) return true;
    }
    // Add the first object to the stack of traversed objects.
    stack.push(a);
    var size = 0, result = true;
    // Deep compare objects.
    for (var key in a) {
      if (hasOwnProperty.call(a, key)) {
        // Count the expected number of properties.
        size++;
        // Deep compare each member.
        if (!(result = hasOwnProperty.call(b, key) && eq(a[key], b[key], stack))) break;
      }
    }
    // Ensure that both objects contain the same number of properties.
    if (result) {
      for (key in b) {
        if (hasOwnProperty.call(b, key) && !size--) break;
      }
      result = !size;
    }
    // Remove the first object from the stack of traversed objects.
    stack.pop();
    return result;
  }

  // Perform a deep comparison to check if two objects are equal.
  _.isEqual = function(a, b) {
    return eq(a, b, []);
  };

  // Is a given array, string, or object empty?
  // An "empty" object has no enumerable own-properties.
  _.isEmpty = function(obj) {
    if (_.isArray(obj) || _.isString(obj)) return obj.length === 0;
    for (var key in obj) if (hasOwnProperty.call(obj, key)) return false;
    return true;
  };

  // Is a given value a DOM element?
  _.isElement = function(obj) {
    return !!(obj && obj.nodeType == 1);
  };

  // Is a given value an array?
  // Delegates to ECMA5's native Array.isArray
  _.isArray = nativeIsArray || function(obj) {
    return toString.call(obj) == '[object Array]';
  };

  // Is a given variable an object?
  _.isObject = function(obj) {
    return obj === Object(obj);
  };

  // Is a given variable an arguments object?
  if (toString.call(arguments) == '[object Arguments]') {
    _.isArguments = function(obj) {
      return toString.call(obj) == '[object Arguments]';
    };
  } else {
    _.isArguments = function(obj) {
      return !!(obj && hasOwnProperty.call(obj, 'callee'));
    };
  }

  // Is a given value a function?
  _.isFunction = function(obj) {
    return toString.call(obj) == '[object Function]';
  };

  // Is a given value a string?
  _.isString = function(obj) {
    return toString.call(obj) == '[object String]';
  };

  // Is a given value a number?
  _.isNumber = function(obj) {
    return toString.call(obj) == '[object Number]';
  };

  // Is the given value `NaN`?
  _.isNaN = function(obj) {
    // `NaN` is the only value for which `===` is not reflexive.
    return obj !== obj;
  };

  // Is a given value a boolean?
  _.isBoolean = function(obj) {
    return obj === true || obj === false || toString.call(obj) == '[object Boolean]';
  };

  // Is a given value a date?
  _.isDate = function(obj) {
    return toString.call(obj) == '[object Date]';
  };

  // Is the given value a regular expression?
  _.isRegExp = function(obj) {
    return toString.call(obj) == '[object RegExp]';
  };

  // Is a given value equal to null?
  _.isNull = function(obj) {
    return obj === null;
  };

  // Is a given variable undefined?
  _.isUndefined = function(obj) {
    return obj === void 0;
  };

  // Utility Functions
  // -----------------

  // Run Underscore.js in *noConflict* mode, returning the `_` variable to its
  // previous owner. Returns a reference to the Underscore object.
  _.noConflict = function() {
    root._ = previousUnderscore;
    return this;
  };

  // Keep the identity function around for default iterators.
  _.identity = function(value) {
    return value;
  };

  // Run a function **n** times.
  _.times = function (n, iterator, context) {
    for (var i = 0; i < n; i++) iterator.call(context, i);
  };

  // Escape a string for HTML interpolation.
  _.escape = function(string) {
    return (''+string).replace(/&(?!\w+;|#\d+;|#x[\da-f]+;)/gi, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;').replace(/'/g, '&#x27;').replace(/\//g,'&#x2F;');
  };

  // Add your own custom functions to the Underscore object, ensuring that
  // they're correctly added to the OOP wrapper as well.
  _.mixin = function(obj) {
    each(_.functions(obj), function(name){
      addToWrapper(name, _[name] = obj[name]);
    });
  };

  // Generate a unique integer id (unique within the entire client session).
  // Useful for temporary DOM ids.
  var idCounter = 0;
  _.uniqueId = function(prefix) {
    var id = idCounter++;
    return prefix ? prefix + id : id;
  };

  // By default, Underscore uses ERB-style template delimiters, change the
  // following template settings to use alternative delimiters.
  _.templateSettings = {
    evaluate    : /<%([\s\S]+?)%>/g,
    interpolate : /<%=([\s\S]+?)%>/g,
    escape      : /<%-([\s\S]+?)%>/g
  };

  // JavaScript micro-templating, similar to John Resig's implementation.
  // Underscore templating handles arbitrary delimiters, preserves whitespace,
  // and correctly escapes quotes within interpolated code.
  _.template = function(str, data) {
    var c  = _.templateSettings;
    var tmpl = 'var __p=[],print=function(){__p.push.apply(__p,arguments);};' +
      'with(obj||{}){__p.push(\'' +
      str.replace(/\\/g, '\\\\')
         .replace(/'/g, "\\'")
         .replace(c.escape, function(match, code) {
           return "',_.escape(" + code.replace(/\\'/g, "'") + "),'";
         })
         .replace(c.interpolate, function(match, code) {
           return "'," + code.replace(/\\'/g, "'") + ",'";
         })
         .replace(c.evaluate || null, function(match, code) {
           return "');" + code.replace(/\\'/g, "'")
                              .replace(/[\r\n\t]/g, ' ') + "__p.push('";
         })
         .replace(/\r/g, '\\r')
         .replace(/\n/g, '\\n')
         .replace(/\t/g, '\\t')
         + "');}return __p.join('');";
    var func = new Function('obj', tmpl);
    return data ? func(data) : func;
  };

  // The OOP Wrapper
  // ---------------

  // If Underscore is called as a function, it returns a wrapped object that
  // can be used OO-style. This wrapper holds altered versions of all the
  // underscore functions. Wrapped objects may be chained.
  var wrapper = function(obj) { this._wrapped = obj; };

  // Expose `wrapper.prototype` as `_.prototype`
  _.prototype = wrapper.prototype;

  // Helper function to continue chaining intermediate results.
  var result = function(obj, chain) {
    return chain ? _(obj).chain() : obj;
  };

  // A method to easily add functions to the OOP wrapper.
  var addToWrapper = function(name, func) {
    wrapper.prototype[name] = function() {
      var args = slice.call(arguments);
      unshift.call(args, this._wrapped);
      return result(func.apply(_, args), this._chain);
    };
  };

  // Add all of the Underscore functions to the wrapper object.
  _.mixin(_);

  // Add all mutator Array functions to the wrapper.
  each(['pop', 'push', 'reverse', 'shift', 'sort', 'splice', 'unshift'], function(name) {
    var method = ArrayProto[name];
    wrapper.prototype[name] = function() {
      method.apply(this._wrapped, arguments);
      return result(this._wrapped, this._chain);
    };
  });

  // Add all accessor Array functions to the wrapper.
  each(['concat', 'join', 'slice'], function(name) {
    var method = ArrayProto[name];
    wrapper.prototype[name] = function() {
      return result(method.apply(this._wrapped, arguments), this._chain);
    };
  });

  // Start chaining a wrapped Underscore object.
  wrapper.prototype.chain = function() {
    this._chain = true;
    return this;
  };

  // Extracts the result from a wrapped and chained object.
  wrapper.prototype.value = function() {
    return this._wrapped;
  };


// BVADDED for string manip

// Underscore.string
// (c) 2010 Esa-Matti Suuronen <esa-matti aet suuronen dot org>
// Underscore.strings is freely distributable under the terms of the MIT license.
// Documentation: https://github.com/epeli/underscore.string
// Some code is borrowed from MooTools and Alexandru Marasteanu.

// Version 2.0.0

(function(root){
  'use strict';
  // Defining helper functions.

  var nativeTrim = String.prototype.trim;

  var parseNumber = function(source) { return source * 1 || 0; };

  var strRepeat = function(i, m) {
    for (var o = []; m > 0; o[--m] = i) {}
    return o.join('');
  };

  var slice = function(a){
    return Array.prototype.slice.call(a);
  };

  var defaultToWhiteSpace = function(characters){
    if (characters) {
      return _s.escapeRegExp(characters);
    }
    return '\\s';
  };

  var sArgs = function(method){
    return function(){
      var args = slice(arguments);
      for(var i=0; i<args.length; i++)
        args[i] = args[i] == null ? '' : '' + args[i];
      return method.apply(null, args);
    };
  };

  // sprintf() for JavaScript 0.7-beta1
  // http://www.diveintojavascript.com/projects/javascript-sprintf
  //
  // Copyright (c) Alexandru Marasteanu <alexaholic [at) gmail (dot] com>
  // All rights reserved.

  var sprintf = (function() {
    function get_type(variable) {
      return Object.prototype.toString.call(variable).slice(8, -1).toLowerCase();
    }

    var str_repeat = strRepeat;

    var str_format = function() {
      if (!str_format.cache.hasOwnProperty(arguments[0])) {
        str_format.cache[arguments[0]] = str_format.parse(arguments[0]);
      }
      return str_format.format.call(null, str_format.cache[arguments[0]], arguments);
    };

    str_format.format = function(parse_tree, argv) {
      var cursor = 1, tree_length = parse_tree.length, node_type = '', arg, output = [], i, k, match, pad, pad_character, pad_length;
      for (i = 0; i < tree_length; i++) {
        node_type = get_type(parse_tree[i]);
        if (node_type === 'string') {
          output.push(parse_tree[i]);
        }
        else if (node_type === 'array') {
          match = parse_tree[i]; // convenience purposes only
          if (match[2]) { // keyword argument
            arg = argv[cursor];
            for (k = 0; k < match[2].length; k++) {
              if (!arg.hasOwnProperty(match[2][k])) {
                throw(sprintf('[_.sprintf] property "%s" does not exist', match[2][k]));
              }
              arg = arg[match[2][k]];
            }
          } else if (match[1]) { // positional argument (explicit)
            arg = argv[match[1]];
          }
          else { // positional argument (implicit)
            arg = argv[cursor++];
          }

          if (/[^s]/.test(match[8]) && (get_type(arg) != 'number')) {
            throw(sprintf('[_.sprintf] expecting number but found %s', get_type(arg)));
          }
          switch (match[8]) {
            case 'b': arg = arg.toString(2); break;
            case 'c': arg = String.fromCharCode(arg); break;
            case 'd': arg = parseInt(arg, 10); break;
            case 'e': arg = match[7] ? arg.toExponential(match[7]) : arg.toExponential(); break;
            case 'f': arg = match[7] ? parseFloat(arg).toFixed(match[7]) : parseFloat(arg); break;
            case 'o': arg = arg.toString(8); break;
            case 's': arg = ((arg = String(arg)) && match[7] ? arg.substring(0, match[7]) : arg); break;
            case 'u': arg = Math.abs(arg); break;
            case 'x': arg = arg.toString(16); break;
            case 'X': arg = arg.toString(16).toUpperCase(); break;
          }
          arg = (/[def]/.test(match[8]) && match[3] && arg >= 0 ? '+'+ arg : arg);
          pad_character = match[4] ? match[4] == '0' ? '0' : match[4].charAt(1) : ' ';
          pad_length = match[6] - String(arg).length;
          pad = match[6] ? str_repeat(pad_character, pad_length) : '';
          output.push(match[5] ? arg + pad : pad + arg);
        }
      }
      return output.join('');
    };

    str_format.cache = {};

    str_format.parse = function(fmt) {
      var _fmt = fmt, match = [], parse_tree = [], arg_names = 0;
      while (_fmt) {
        if ((match = /^[^\x25]+/.exec(_fmt)) !== null) {
          parse_tree.push(match[0]);
        }
        else if ((match = /^\x25{2}/.exec(_fmt)) !== null) {
          parse_tree.push('%');
        }
        else if ((match = /^\x25(?:([1-9]\d*)\$|\(([^\)]+)\))?(\+)?(0|'[^$])?(-)?(\d+)?(?:\.(\d+))?([b-fosuxX])/.exec(_fmt)) !== null) {
          if (match[2]) {
            arg_names |= 1;
            var field_list = [], replacement_field = match[2], field_match = [];
            if ((field_match = /^([a-z_][a-z_\d]*)/i.exec(replacement_field)) !== null) {
              field_list.push(field_match[1]);
              while ((replacement_field = replacement_field.substring(field_match[0].length)) !== '') {
                if ((field_match = /^\.([a-z_][a-z_\d]*)/i.exec(replacement_field)) !== null) {
                  field_list.push(field_match[1]);
                }
                else if ((field_match = /^\[(\d+)\]/.exec(replacement_field)) !== null) {
                  field_list.push(field_match[1]);
                }
                else {
                  throw('[_.sprintf] huh?');
                }
              }
            }
            else {
              throw('[_.sprintf] huh?');
            }
            match[2] = field_list;
          }
          else {
            arg_names |= 2;
          }
          if (arg_names === 3) {
            throw('[_.sprintf] mixing positional and named placeholders is not (yet) supported');
          }
          parse_tree.push(match);
        }
        else {
          throw('[_.sprintf] huh?');
        }
        _fmt = _fmt.substring(match[0].length);
      }
      return parse_tree;
    };

    return str_format;
  })();



  // Defining underscore.string

  var _s = {

    VERSION: '1.2.0',

    isBlank: sArgs(function(str){
      return (/^\s*$/).test(str);
    }),

    stripTags: sArgs(function(str){
      return str.replace(/<\/?[^>]+>/ig, '');
    }),

    capitalize : sArgs(function(str) {
      return str.charAt(0).toUpperCase() + str.substring(1).toLowerCase();
    }),

    chop: sArgs(function(str, step){
      step = parseNumber(step) || str.length;
      var arr = [];
      for (var i = 0; i < str.length;) {
        arr.push(str.slice(i,i + step));
        i = i + step;
      }
      return arr;
    }),

    clean: sArgs(function(str){
      return _s.strip(str.replace(/\s+/g, ' '));
    }),

    count: sArgs(function(str, substr){
      var count = 0, index;
      for (var i=0; i < str.length;) {
        index = str.indexOf(substr, i);
        index >= 0 && count++;
        i = i + (index >= 0 ? index : 0) + substr.length;
      }
      return count;
    }),

    chars: sArgs(function(str) {
      return str.split('');
    }),

    escapeHTML: sArgs(function(str) {
      return str.replace(/&/g,'&amp;').replace(/</g,'&lt;').replace(/>/g,'&gt;')
                            .replace(/"/g, '&quot;').replace(/'/g, "&apos;");
    }),

    unescapeHTML: sArgs(function(str) {
      return str.replace(/&lt;/g, '<').replace(/&gt;/g, '>')
                            .replace(/&quot;/g, '"').replace(/&apos;/g, "'").replace(/&amp;/g, '&');
    }),

    escapeRegExp: sArgs(function(str){
      // From MooTools core 1.2.4
      return str.replace(/([-.*+?^${}()|[\]\/\\])/g, '\\$1');
    }),

    insert: sArgs(function(str, i, substr){
      var arr = str.split('');
      arr.splice(parseNumber(i), 0, substr);
      return arr.join('');
    }),

    include: sArgs(function(str, needle){
      return str.indexOf(needle) !== -1;
    }),

    join: sArgs(function(sep) {
      var args = slice(arguments);
      return args.join(args.shift());
    }),

    lines: sArgs(function(str) {
      return str.split("\n");
    }),

    reverse: sArgs(function(str){
        return Array.prototype.reverse.apply(String(str).split('')).join('');
    }),

    splice: sArgs(function(str, i, howmany, substr){
      var arr = str.split('');
      arr.splice(parseNumber(i), parseNumber(howmany), substr);
      return arr.join('');
    }),

    startsWith: sArgs(function(str, starts){
      return str.length >= starts.length && str.substring(0, starts.length) === starts;
    }),

    endsWith: sArgs(function(str, ends){
      return str.length >= ends.length && str.substring(str.length - ends.length) === ends;
    }),

    succ: sArgs(function(str){
      var arr = str.split('');
      arr.splice(str.length-1, 1, String.fromCharCode(str.charCodeAt(str.length-1) + 1));
      return arr.join('');
    }),

    titleize: sArgs(function(str){
      var arr = str.split(' '),
          word;
      for (var i=0; i < arr.length; i++) {
        word = arr[i].split('');
        if(typeof word[0] !== 'undefined') word[0] = word[0].toUpperCase();
        i+1 === arr.length ? arr[i] = word.join('') : arr[i] = word.join('') + ' ';
      }
      return arr.join('');
    }),

    camelize: sArgs(function(str){
      return _s.trim(str).replace(/(\-|_|\s)+(.)?/g, function(match, separator, chr) {
        return chr ? chr.toUpperCase() : '';
      });
    }),

    underscored: function(str){
      return _s.trim(str).replace(/([a-z\d])([A-Z]+)/g, '$1_$2').replace(/\-|\s+/g, '_').toLowerCase();
    },

    dasherize: function(str){
      return _s.trim(str).replace(/([a-z\d])([A-Z]+)/g, '$1-$2').replace(/^([A-Z]+)/, '-$1').replace(/\_|\s+/g, '-').toLowerCase();
    },

    humanize: function(str){
      return _s.capitalize(this.underscored(str).replace(/_id$/,'').replace(/_/g, ' '));
    },

    trim: sArgs(function(str, characters){
      if (!characters && nativeTrim) {
        return nativeTrim.call(str);
      }
      characters = defaultToWhiteSpace(characters);
      return str.replace(new RegExp('\^[' + characters + ']+|[' + characters + ']+$', 'g'), '');
    }),

    ltrim: sArgs(function(str, characters){
      characters = defaultToWhiteSpace(characters);
      return str.replace(new RegExp('\^[' + characters + ']+', 'g'), '');
    }),

    rtrim: sArgs(function(str, characters){
      characters = defaultToWhiteSpace(characters);
      return str.replace(new RegExp('[' + characters + ']+$', 'g'), '');
    }),

    truncate: sArgs(function(str, length, truncateStr){
      truncateStr = truncateStr || '...';
      length = parseNumber(length);
      return str.length > length ? str.slice(0,length) + truncateStr : str;
    }),

    /**
     * _s.prune: a more elegant version of truncate
     * prune extra chars, never leaving a half-chopped word.
     * @author github.com/sergiokas
     */
    prune: sArgs(function(str, length, pruneStr){
      // Function to check word/digit chars including non-ASCII encodings. 
      var isWordChar = function(c) { return ((c.toUpperCase() != c.toLowerCase()) || /[-_\d]/.test(c)); }
      
      var template = '';
      var pruned = '';
      var i = 0;
      
      // Set default values
      pruneStr = pruneStr || '...';
      length = parseNumber(length);
      
      // Convert to an ASCII string to avoid problems with unicode chars.
      for (i in str) {
        template += (isWordChar(str[i]))?'A':' ';
      } 

      // Check if we're in the middle of a word
      if( template.substring(length-1, length+1).search(/^\w\w$/) === 0 )
        pruned = _s.rtrim(template.slice(0,length).replace(/([\W][\w]*)$/,''));
      else
        pruned = _s.rtrim(template.slice(0,length));

      pruned = pruned.replace(/\W+$/,'');

      return (pruned.length+pruneStr.length>str.length) ? str : str.substring(0, pruned.length)+pruneStr;
    }),

    words: function(str, delimiter) {
      return String(str).split(delimiter || " ");
    },

    pad: sArgs(function(str, length, padStr, type) {
      var padding = '',
          padlen  = 0;

      length = parseNumber(length);

      if (!padStr) { padStr = ' '; }
      else if (padStr.length > 1) { padStr = padStr.charAt(0); }
      switch(type) {
        case 'right':
          padlen = (length - str.length);
          padding = strRepeat(padStr, padlen);
          str = str+padding;
          break;
        case 'both':
          padlen = (length - str.length);
          padding = {
            'left' : strRepeat(padStr, Math.ceil(padlen/2)),
            'right': strRepeat(padStr, Math.floor(padlen/2))
          };
          str = padding.left+str+padding.right;
          break;
        default: // 'left'
          padlen = (length - str.length);
          padding = strRepeat(padStr, padlen);;
          str = padding+str;
        }
      return str;
    }),

    lpad: function(str, length, padStr) {
      return _s.pad(str, length, padStr);
    },

    rpad: function(str, length, padStr) {
      return _s.pad(str, length, padStr, 'right');
    },

    lrpad: function(str, length, padStr) {
      return _s.pad(str, length, padStr, 'both');
    },

    sprintf: sprintf,

    vsprintf: function(fmt, argv){
      argv.unshift(fmt);
      return sprintf.apply(null, argv);
    },

    toNumber: function(str, decimals) {
      var num = parseNumber(parseNumber(str).toFixed(parseNumber(decimals)));
      return (!(num === 0 && (str !== "0" && str !== 0))) ? num : Number.NaN;
    },

    strRight: sArgs(function(sourceStr, sep){
      var pos =  (!sep) ? -1 : sourceStr.indexOf(sep);
      return (pos != -1) ? sourceStr.slice(pos+sep.length, sourceStr.length) : sourceStr;
    }),

    strRightBack: sArgs(function(sourceStr, sep){
      var pos =  (!sep) ? -1 : sourceStr.lastIndexOf(sep);
      return (pos != -1) ? sourceStr.slice(pos+sep.length, sourceStr.length) : sourceStr;
    }),

    strLeft: sArgs(function(sourceStr, sep){
      var pos = (!sep) ? -1 : sourceStr.indexOf(sep);
      return (pos != -1) ? sourceStr.slice(0, pos) : sourceStr;
    }),

    strLeftBack: sArgs(function(sourceStr, sep){
      var pos = sourceStr.lastIndexOf(sep);
      return (pos != -1) ? sourceStr.slice(0, pos) : sourceStr;
    }),

    exports: function() {
      var result = {};

      for (var prop in this) {
        if (!this.hasOwnProperty(prop) || prop == 'include' || prop == 'contains' || prop == 'reverse') continue;
        result[prop] = this[prop];
      }

      return result;
    }

  };

  // Aliases

  _s.strip    = _s.trim;
  _s.lstrip   = _s.ltrim;
  _s.rstrip   = _s.rtrim;
  _s.center   = _s.lrpad;
  _s.ljust    = _s.lpad;
  _s.rjust    = _s.rpad;
  _s.contains = _s.include;

  
  _.string = _s;
  _.str    = _s;
}(root));

// Register as a named module with AMD.
define(function() {
  return _;
});
}).call({});