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lodash.js
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lodash.js
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/*!
* Lo-Dash v0.5.2 <http://lodash.com>
* Copyright 2012 John-David Dalton <http://allyoucanleet.com/>
* Based on Underscore.js 1.3.3, copyright 2009-2012 Jeremy Ashkenas, DocumentCloud Inc.
* <http://documentcloud.github.com/underscore>
* Available under MIT license <http://lodash.com/license>
*/
;(function(window, undefined) {
'use strict';
/**
* Used to cache the last `_.templateSettings.evaluate` delimiter to avoid
* unnecessarily assigning `reEvaluateDelimiter` a new generated regexp.
* Assigned in `_.template`.
*/
var lastEvaluateDelimiter;
/**
* Used to cache the last template `options.variable` to avoid unnecessarily
* assigning `reDoubleVariable` a new generated regexp. Assigned in `_.template`.
*/
var lastVariable;
/**
* Used to match potentially incorrect data object references, like `obj.obj`,
* in compiled templates. Assigned in `_.template`.
*/
var reDoubleVariable;
/**
* Used to match "evaluate" delimiters, including internal delimiters,
* in template text. Assigned in `_.template`.
*/
var reEvaluateDelimiter;
/** Detect free variable `exports` */
var freeExports = typeof exports == 'object' && exports &&
(typeof global == 'object' && global && global == global.global && (window = global), exports);
/** Native prototype shortcuts */
var ArrayProto = Array.prototype,
BoolProto = Boolean.prototype,
ObjectProto = Object.prototype,
NumberProto = Number.prototype,
StringProto = String.prototype;
/** Used to generate unique IDs */
var idCounter = 0;
/** Used to restore the original `_` reference in `noConflict` */
var oldDash = window._;
/** Used to detect delimiter values that should be processed by `tokenizeEvaluate` */
var reComplexDelimiter = /[-+=!~*%&^<>|{(\/]|\[\D|\b(?:delete|in|instanceof|new|typeof|void)\b/;
/** 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 regexp flags from their coerced string values */
var reFlags = /\w*$/;
/** Used to insert the data object variable into compiled template source */
var reInsertVariable = /(?:__e|__t = )\(\s*(?![\d\s"']|this\.)/g;
/** Used to detect if a method is native */
var reNative = RegExp('^' +
(ObjectProto.valueOf + '')
.replace(/[.*+?^=!:${}()|[\]\/\\]/g, '\\$&')
.replace(/valueOf|for [^\]]+/g, '.+?') + '$'
);
/** Used to match tokens in template text */
var reToken = /__token__(\d+)/g;
/** Used to match unescaped characters in strings for inclusion in HTML */
var reUnescapedHtml = /[&<"']/g;
/** Used to match unescaped characters in compiled string literals */
var reUnescapedString = /['\n\r\t\u2028\u2029\\]/g;
/** Used to fix the JScript [[DontEnum]] bug */
var shadowed = [
'constructor', 'hasOwnProperty', 'isPrototypeOf', 'propertyIsEnumerable',
'toLocaleString', 'toString', 'valueOf'
];
/** Used to make template sourceURLs easier to identify */
var templateCounter = 0;
/** Used to replace template delimiters */
var token = '__token__';
/** Used to store tokenized template text snippets */
var tokenized = [];
/** Native method shortcuts */
var concat = ArrayProto.concat,
hasOwnProperty = ObjectProto.hasOwnProperty,
push = ArrayProto.push,
propertyIsEnumerable = ObjectProto.propertyIsEnumerable,
slice = ArrayProto.slice,
toString = ObjectProto.toString;
/* Native method shortcuts for methods with the same name as other `lodash` methods */
var nativeBind = reNative.test(nativeBind = slice.bind) && nativeBind,
nativeIsArray = reNative.test(nativeIsArray = Array.isArray) && nativeIsArray,
nativeIsFinite = window.isFinite,
nativeKeys = reNative.test(nativeKeys = Object.keys) && nativeKeys;
/** `Object#toString` result shortcuts */
var argsClass = '[object Arguments]',
arrayClass = '[object Array]',
boolClass = '[object Boolean]',
dateClass = '[object Date]',
funcClass = '[object Function]',
numberClass = '[object Number]',
objectClass = '[object Object]',
regexpClass = '[object RegExp]',
stringClass = '[object String]';
/** Timer shortcuts */
var clearTimeout = window.clearTimeout,
setTimeout = window.setTimeout;
/**
* Detect the JScript [[DontEnum]] bug:
* In IE < 9 an objects own properties, shadowing non-enumerable ones, are
* made non-enumerable as well.
*/
var hasDontEnumBug;
/** Detect if own properties are iterated after inherited properties (IE < 9) */
var iteratesOwnLast;
/** Detect if an `arguments` object's indexes are non-enumerable (IE < 9) */
var noArgsEnum = true;
(function() {
var props = [];
function ctor() { this.x = 1; }
ctor.prototype = { 'valueOf': 1, 'y': 1 };
for (var prop in new ctor) { props.push(prop); }
for (prop in arguments) { noArgsEnum = !prop; }
hasDontEnumBug = (props + '').length < 4;
iteratesOwnLast = props[0] != 'x';
}(1));
/** Detect if an `arguments` object's [[Class]] is unresolvable (Firefox < 4, IE < 9) */
var noArgsClass = !isArguments(arguments);
/** Detect if `Array#slice` cannot be used to convert strings to arrays (Opera < 10.52) */
var noArraySliceOnStrings = slice.call('x')[0] != 'x';
/**
* Detect lack of support for accessing string characters by index:
* IE < 8 can't access characters by index and IE 8 can only access
* characters by index on string literals.
*/
var noCharByIndex = ('x'[0] + Object('x')[0]) != 'xx';
/**
* Detect if a node's [[Class]] is unresolvable (IE < 9)
* and that the JS engine won't error when attempting to coerce an object to
* a string without a `toString` property value of `typeof` "function".
*/
try {
var noNodeClass = ({ 'toString': 0 } + '', toString.call(window.document || 0) == objectClass);
} catch(e) { }
/* Detect if `Function#bind` exists and is inferred to be fast (all but V8) */
var isBindFast = nativeBind && /\n|Opera/.test(nativeBind + toString.call(window.opera));
/* Detect if `Object.keys` exists and is inferred to be fast (IE, Opera, V8) */
var isKeysFast = nativeKeys && /^.+$|true/.test(nativeKeys + !!window.attachEvent);
/* Detect if strict mode, "use strict", is inferred to be fast (V8) */
var isStrictFast = !isBindFast;
/** Detect if sourceURL syntax is usable without erroring */
try {
// The JS engine in Adobe products, like InDesign, will throw a syntax error
// when it encounters a single line comment beginning with the `@` symbol.
// The JS engine in Narwhal will generate the function `function anonymous(){//}`
// and throw a syntax error. In IE, `@` symbols are part of its non-standard
// conditional compilation support. The `@cc_on` statement activates its support
// while the trailing ` !` induces a syntax error to exlude it. Compatibility
// modes in IE > 8 require a space before the `!` to induce a syntax error.
// See http://msdn.microsoft.com/en-us/library/121hztk3(v=vs.94).aspx
var useSourceURL = (Function('//@cc_on !')(), true);
} catch(e){ }
/** Used to identify object classifications that are array-like */
var arrayLikeClasses = {};
arrayLikeClasses[boolClass] = arrayLikeClasses[dateClass] = arrayLikeClasses[funcClass] =
arrayLikeClasses[numberClass] = arrayLikeClasses[objectClass] = arrayLikeClasses[regexpClass] = false;
arrayLikeClasses[argsClass] = arrayLikeClasses[arrayClass] = arrayLikeClasses[stringClass] = true;
/** Used to identify object classifications that `_.clone` supports */
var cloneableClasses = {};
cloneableClasses[argsClass] = cloneableClasses[funcClass] = false;
cloneableClasses[arrayClass] = cloneableClasses[boolClass] = cloneableClasses[dateClass] =
cloneableClasses[numberClass] = cloneableClasses[objectClass] = cloneableClasses[regexpClass] =
cloneableClasses[stringClass] = true;
/**
* Used to escape characters for inclusion in HTML.
* The `>` and `/` characters don't require escaping in HTML and have no
* special meaning unless they're part of a tag or an unquoted attribute value
* http://mathiasbynens.be/notes/ambiguous-ampersands (semi-related fun fact)
*/
var htmlEscapes = {
'&': '&',
'<': '<',
'"': '"',
"'": '''
};
/** Used to determine if values are of the language type Object */
var objectTypes = {
'boolean': false,
'function': true,
'object': true,
'number': false,
'string': false,
'undefined': false,
'unknown': true
};
/** Used to escape characters for inclusion in compiled string literals */
var stringEscapes = {
'\\': '\\',
"'": "'",
'\n': 'n',
'\r': 'r',
'\t': 't',
'\u2028': 'u2028',
'\u2029': 'u2029'
};
/*--------------------------------------------------------------------------*/
/**
* The `lodash` function.
*
* @name _
* @constructor
* @param {Mixed} value The value to wrap in a `LoDash` instance.
* @returns {Object} Returns a `LoDash` instance.
*/
function lodash(value) {
// allow invoking `lodash` without the `new` operator
return new LoDash(value);
}
/**
* Creates a `LoDash` instance that wraps a value to allow chaining.
*
* @private
* @constructor
* @param {Mixed} value The value to wrap.
*/
function LoDash(value) {
// exit early if already wrapped
if (value && value._wrapped) {
return value;
}
this._wrapped = value;
}
/**
* 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.
*
* @static
* @memberOf _.templateSettings
* @type RegExp
*/
'escape': /<%-([\s\S]+?)%>/g,
/**
* Used to detect code to be evaluated.
*
* @static
* @memberOf _.templateSettings
* @type RegExp
*/
'evaluate': /<%([\s\S]+?)%>/g,
/**
* Used to detect `data` property values to inject.
*
* @static
* @memberOf _.templateSettings
* @type RegExp
*/
'interpolate': /<%=([\s\S]+?)%>/g,
/**
* Used to reference the data object in the template text.
*
* @static
* @memberOf _.templateSettings
* @type String
*/
'variable': ''
};
/*--------------------------------------------------------------------------*/
/**
* The template used to create iterator functions.
*
* @private
* @param {Obect} data The data object used to populate the text.
* @returns {String} Returns the interpolated text.
*/
var iteratorTemplate = template(
// conditional strict mode
'<% if (useStrict) { %>\'use strict\';\n<% } %>' +
// the `iteratee` may be reassigned by the `top` snippet
'var index, value, iteratee = <%= firstArg %>, ' +
// assign the `result` variable an initial value
'result<% if (init) { %> = <%= init %><% } %>;\n' +
// add code to exit early or do so if the first argument is falsey
'<%= exit %>;\n' +
// add code after the exit snippet but before the iteration branches
'<%= top %>;\n' +
// the following branch is for iterating arrays and array-like objects
'<% if (arrayBranch) { %>' +
'var length = iteratee.length; index = -1;' +
' <% if (objectBranch) { %>\nif (length > -1 && length === length >>> 0) {<% } %>' +
// add support for accessing string characters by index if needed
' <% if (noCharByIndex) { %>\n' +
' if (toString.call(iteratee) == stringClass) {\n' +
' iteratee = iteratee.split(\'\')\n' +
' }' +
' <% } %>\n' +
' <%= arrayBranch.beforeLoop %>;\n' +
' while (++index < length) {\n' +
' value = iteratee[index];\n' +
' <%= arrayBranch.inLoop %>\n' +
' }' +
' <% if (objectBranch) { %>\n}<% } %>' +
'<% } %>' +
// the following branch is for iterating an object's own/inherited properties
'<% if (objectBranch) { %>' +
' <% if (arrayBranch) { %>\nelse {' +
// add support for iterating over `arguments` objects if needed
' <% } else if (noArgsEnum) { %>\n' +
' var length = iteratee.length; index = -1;\n' +
' if (length && isArguments(iteratee)) {\n' +
' while (++index < length) {\n' +
' value = iteratee[index += \'\'];\n' +
' <%= objectBranch.inLoop %>\n' +
' }\n' +
' } else {' +
' <% } %>' +
' <% if (!hasDontEnumBug) { %>\n' +
' var skipProto = typeof iteratee == \'function\' && \n' +
' propertyIsEnumerable.call(iteratee, \'prototype\');\n' +
' <% } %>' +
// iterate own properties using `Object.keys` if it's fast
' <% if (isKeysFast && useHas) { %>\n' +
' var ownIndex = -1,\n' +
' ownProps = objectTypes[typeof iteratee] ? nativeKeys(iteratee) : [],\n' +
' length = ownProps.length;\n\n' +
' <%= objectBranch.beforeLoop %>;\n' +
' while (++ownIndex < length) {\n' +
' index = ownProps[ownIndex];\n' +
' <% if (!hasDontEnumBug) { %>if (!(skipProto && index == \'prototype\')) {\n <% } %>' +
' value = iteratee[index];\n' +
' <%= objectBranch.inLoop %>\n' +
' <% if (!hasDontEnumBug) { %>}\n<% } %>' +
' }' +
// else using a for-in loop
' <% } else { %>\n' +
' <%= objectBranch.beforeLoop %>;\n' +
' for (index in iteratee) {' +
' <% if (hasDontEnumBug) { %>\n' +
' <% if (useHas) { %>if (hasOwnProperty.call(iteratee, index)) {\n <% } %>' +
' value = iteratee[index];\n' +
' <%= objectBranch.inLoop %>;\n' +
' <% if (useHas) { %>}<% } %>' +
// Firefox < 3.6, Opera > 9.50 - Opera < 11.60, and Safari < 5.1
// (if the prototype or a property on the prototype has been set)
// incorrectly sets a function's `prototype` property [[Enumerable]]
// value to `true`. Because of this Lo-Dash standardizes on skipping
// the the `prototype` property of functions regardless of its
// [[Enumerable]] value.
' <% } else { %>\n' +
' if (!(skipProto && index == \'prototype\')<% if (useHas) { %> &&\n' +
' hasOwnProperty.call(iteratee, index)<% } %>) {\n' +
' value = iteratee[index];\n' +
' <%= objectBranch.inLoop %>\n' +
' }' +
' <% } %>\n' +
' }' +
' <% } %>' +
// Because IE < 9 can't set the `[[Enumerable]]` attribute of an
// existing property and the `constructor` property of a prototype
// defaults to non-enumerable, Lo-Dash skips the `constructor`
// property when it infers it's iterating over a `prototype` object.
' <% if (hasDontEnumBug) { %>\n\n' +
' var ctor = iteratee.constructor;\n' +
' <% for (var k = 0; k < 7; k++) { %>\n' +
' index = \'<%= shadowed[k] %>\';\n' +
' if (<%' +
' if (shadowed[k] == \'constructor\') {' +
' %>!(ctor && ctor.prototype === iteratee) && <%' +
' } %>hasOwnProperty.call(iteratee, index)) {\n' +
' value = iteratee[index];\n' +
' <%= objectBranch.inLoop %>\n' +
' }' +
' <% } %>' +
' <% } %>' +
' <% if (arrayBranch || noArgsEnum) { %>\n}<% } %>' +
'<% } %>\n' +
// add code to the bottom of the iteration function
'<%= bottom %>;\n' +
// finally, return the `result`
'return result'
);
/**
* Reusable iterator options shared by
* `every`, `filter`, `find`, `forEach`, `forIn`, `forOwn`, `groupBy`, `map`,
* `reject`, `some`, and `sortBy`.
*/
var baseIteratorOptions = {
'args': 'collection, callback, thisArg',
'init': 'collection',
'top':
'if (!callback) {\n' +
' callback = identity\n' +
'}\n' +
'else if (thisArg) {\n' +
' callback = iteratorBind(callback, thisArg)\n' +
'}',
'inLoop': 'if (callback(value, index, collection) === false) return result'
};
/** Reusable iterator options for `countBy`, `groupBy`, and `sortBy` */
var countByIteratorOptions = {
'init': '{}',
'top':
'var prop;\n' +
'if (typeof callback != \'function\') {\n' +
' var valueProp = callback;\n' +
' callback = function(value) { return value[valueProp] }\n' +
'}\n' +
'else if (thisArg) {\n' +
' callback = iteratorBind(callback, thisArg)\n' +
'}',
'inLoop':
'prop = callback(value, index, collection);\n' +
'(hasOwnProperty.call(result, prop) ? result[prop]++ : result[prop] = 1)'
};
/** Reusable iterator options for `every` and `some` */
var everyIteratorOptions = {
'init': 'true',
'inLoop': 'if (!callback(value, index, collection)) return !result'
};
/** Reusable iterator options for `defaults` and `extend` */
var extendIteratorOptions = {
'useHas': false,
'useStrict': false,
'args': 'object',
'init': 'object',
'top':
'for (var argsIndex = 1, argsLength = arguments.length; argsIndex < argsLength; argsIndex++) {\n' +
' if (iteratee = arguments[argsIndex]) {',
'inLoop': 'result[index] = value',
'bottom': ' }\n}'
};
/** Reusable iterator options for `filter`, `reject`, and `where` */
var filterIteratorOptions = {
'init': '[]',
'inLoop': 'callback(value, index, collection) && result.push(value)'
};
/** Reusable iterator options for `find`, `forEach`, `forIn`, and `forOwn` */
var forEachIteratorOptions = {
'top': 'if (thisArg) callback = iteratorBind(callback, thisArg)'
};
/** Reusable iterator options for `forIn` and `forOwn` */
var forOwnIteratorOptions = {
'inLoop': {
'object': baseIteratorOptions.inLoop
}
};
/** Reusable iterator options for `invoke`, `map`, `pluck`, and `sortBy` */
var mapIteratorOptions = {
'init': '',
'exit': 'if (!collection) return []',
'beforeLoop': {
'array': 'result = Array(length)',
'object': 'result = ' + (isKeysFast ? 'Array(length)' : '[]')
},
'inLoop': {
'array': 'result[index] = callback(value, index, collection)',
'object': 'result' + (isKeysFast ? '[ownIndex] = ' : '.push') + '(callback(value, index, collection))'
}
};
/*--------------------------------------------------------------------------*/
/**
* Creates a new function optimized for searching large arrays for a given `value`,
* starting at `fromIndex`, using strict equality for comparisons, i.e. `===`.
*
* @private
* @param {Array} array The array to search.
* @param {Mixed} value The value to search for.
* @param {Number} [fromIndex=0] The index to start searching from.
* @param {Number} [largeSize=30] The length at which an array is considered large.
* @returns {Boolean} Returns `true` if `value` is found, else `false`.
*/
function cachedContains(array, fromIndex, largeSize) {
fromIndex || (fromIndex = 0);
var length = array.length,
isLarge = (length - fromIndex) >= (largeSize || 30),
cache = isLarge ? {} : array;
if (isLarge) {
// init value cache
var key,
index = fromIndex - 1;
while (++index < length) {
// manually coerce `value` to string because `hasOwnProperty`, in some
// older versions of Firefox, coerces objects incorrectly
key = array[index] + '';
(hasOwnProperty.call(cache, key) ? cache[key] : (cache[key] = [])).push(array[index]);
}
}
return function(value) {
if (isLarge) {
var key = value + '';
return hasOwnProperty.call(cache, key) && indexOf(cache[key], value) > -1;
}
return indexOf(cache, value, fromIndex) > -1;
}
}
/**
* Creates compiled iteration functions. The iteration function will be created
* to iterate over only objects if the first argument of `options.args` is
* "object" or `options.inLoop.array` is falsey.
*
* @private
* @param {Object} [options1, options2, ...] The compile options objects.
*
* useHas - A boolean to specify whether or not to use `hasOwnProperty` checks
* in the object loop.
*
* useStrict - A boolean to specify whether or not to include the ES5
* "use strict" directive.
*
* args - A string of comma separated arguments the iteration function will
* accept.
*
* init - A string to specify the initial value of the `result` variable.
*
* exit - A string of code to use in place of the default exit-early check
* of `if (!arguments[0]) return result`.
*
* top - A string of code to execute after the exit-early check but before
* the iteration branches.
*
* beforeLoop - A string or object containing an "array" or "object" property
* of code to execute before the array or object loops.
*
* inLoop - A string or object containing an "array" or "object" property
* of code to execute in the array or object loops.
*
* bottom - A string of code to execute after the iteration branches but
* before the `result` is returned.
*
* @returns {Function} Returns the compiled function.
*/
function createIterator() {
var object,
prop,
value,
index = -1,
length = arguments.length;
// merge options into a template data object
var data = {
'bottom': '',
'exit': '',
'init': '',
'top': '',
'arrayBranch': { 'beforeLoop': '' },
'objectBranch': { 'beforeLoop': '' }
};
while (++index < length) {
object = arguments[index];
for (prop in object) {
value = (value = object[prop]) == null ? '' : value;
// keep this regexp explicit for the build pre-process
if (/beforeLoop|inLoop/.test(prop)) {
if (typeof value == 'string') {
value = { 'array': value, 'object': value };
}
data.arrayBranch[prop] = value.array || '';
data.objectBranch[prop] = value.object || '';
} else {
data[prop] = value;
}
}
}
// set additional template `data` values
var args = data.args,
firstArg = /^[^,]+/.exec(args)[0],
useStrict = data.useStrict;
data.firstArg = firstArg;
data.hasDontEnumBug = hasDontEnumBug;
data.isKeysFast = isKeysFast;
data.noArgsEnum = noArgsEnum;
data.shadowed = shadowed;
data.useHas = data.useHas !== false;
data.useStrict = useStrict == null ? isStrictFast : useStrict;
if (!('noCharByIndex' in data)) {
data.noCharByIndex = noCharByIndex;
}
if (!data.exit) {
data.exit = 'if (!' + firstArg + ') return result';
}
if (firstArg != 'collection' || !data.arrayBranch.inLoop) {
data.arrayBranch = null;
}
// create the function factory
var factory = Function(
'arrayLikeClasses, ArrayProto, bind, compareAscending, concat, forIn, ' +
'hasOwnProperty, identity, indexOf, isArguments, isArray, isFunction, ' +
'isPlainObject, iteratorBind, objectClass, objectTypes, nativeKeys, ' +
'propertyIsEnumerable, slice, stringClass, toString',
'var callee = function(' + args + ') {\n' + iteratorTemplate(data) + '\n};\n' +
'return callee'
);
// return the compiled function
return factory(
arrayLikeClasses, ArrayProto, bind, compareAscending, concat, forIn,
hasOwnProperty, identity, indexOf, isArguments, isArray, isFunction,
isPlainObject, iteratorBind, objectClass, objectTypes, nativeKeys,
propertyIsEnumerable, slice, stringClass, toString
);
}
/**
* Used by `sortBy` to compare transformed `collection` values, stable sorting
* them in ascending order.
*
* @private
* @param {Object} a The object to compare to `b`.
* @param {Object} b The object to compare to `a`.
* @returns {Number} Returns the sort order indicator of `1` or `-1`.
*/
function compareAscending(a, b) {
var ai = a.index,
bi = b.index;
a = a.criteria;
b = b.criteria;
if (a === undefined) {
return 1;
}
if (b === undefined) {
return -1;
}
// ensure a stable sort in V8 and other engines
// http://code.google.com/p/v8/issues/detail?id=90
return a < b ? -1 : a > b ? 1 : ai < bi ? -1 : 1;
}
/**
* Used by `template` to replace tokens with their corresponding code snippets.
*
* @private
* @param {String} match The matched token.
* @param {String} index The `tokenized` index of the code snippet.
* @returns {String} Returns the code snippet.
*/
function detokenize(match, index) {
return tokenized[index];
}
/**
* Used by `template` to escape characters for inclusion in compiled
* string literals.
*
* @private
* @param {String} match The matched character to escape.
* @returns {String} Returns the escaped character.
*/
function escapeStringChar(match) {
return '\\' + stringEscapes[match];
}
/**
* Used by `escape` to escape characters for inclusion in HTML.
*
* @private
* @param {String} match The matched character to escape.
* @returns {String} Returns the escaped character.
*/
function escapeHtmlChar(match) {
return htmlEscapes[match];
}
/**
* Checks if a given `value` is an object created by the `Object` constructor
* assuming objects created by the `Object` constructor have no inherited
* enumerable properties and that there are no `Object.prototype` extensions.
*
* @private
* @param {Mixed} value The value to check.
* @param {Boolean} [skipArgsCheck=false] Internally used to skip checks for
* `arguments` objects.
* @returns {Boolean} Returns `true` if the `value` is a plain `Object` object,
* else `false`.
*/
function isPlainObject(value, skipArgsCheck) {
// avoid non-objects and false positives for `arguments` objects
var result = false;
if (!(value && typeof value == 'object') || (!skipArgsCheck && isArguments(value))) {
return result;
}
// IE < 9 presents DOM nodes as `Object` objects except they have `toString`
// methods that are `typeof` "string" and still can coerce nodes to strings.
// Also check that the constructor is `Object` (i.e. `Object instanceof Object`)
var ctor = value.constructor;
if ((!noNodeClass || !(typeof value.toString != 'function' && typeof (value + '') == 'string')) &&
(!isFunction(ctor) || ctor instanceof ctor)) {
// IE < 9 iterates inherited properties before own properties. If the first
// iterated property is an object's own property then there are no inherited
// enumerable properties.
if (iteratesOwnLast) {
forIn(value, function(objValue, objKey) {
result = !hasOwnProperty.call(value, objKey);
return false;
});
return result === 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.
forIn(value, function(objValue, objKey) {
result = objKey;
});
return result === false || hasOwnProperty.call(value, result);
}
return result;
}
/**
* Creates a new function that, when called, invokes `func` with the `this`
* binding of `thisArg` and the arguments (value, index, object).
*
* @private
* @param {Function} func The function to bind.
* @param {Mixed} [thisArg] The `this` binding of `func`.
* @returns {Function} Returns the new bound function.
*/
function iteratorBind(func, thisArg) {
return function(value, index, object) {
return func.call(thisArg, value, index, object);
};
}
/**
* A no-operation function.
*
* @private
*/
function noop() {
// no operation performed
}
/**
* Used by `template` to replace "escape" template delimiters with tokens.
*
* @private
* @param {String} match The matched template delimiter.
* @param {String} value The delimiter value.
* @returns {String} Returns a token.
*/
function tokenizeEscape(match, value) {
if (match && reComplexDelimiter.test(value)) {
return '<e%-' + value + '%>';
}
var index = tokenized.length;
tokenized[index] = "' +\n__e(" + value + ") +\n'";
return token + index;
}
/**
* Used by `template` to replace "evaluate" template delimiters, or complex
* "escape" and "interpolate" delimiters, with tokens.
*
* @private
* @param {String} match The matched template delimiter.
* @param {String} escapeValue The complex "escape" delimiter value.
* @param {String} interpolateValue The complex "interpolate" delimiter value.
* @param {String} [evaluateValue] The "evaluate" delimiter value.
* @returns {String} Returns a token.
*/
function tokenizeEvaluate(match, escapeValue, interpolateValue, evaluateValue) {
if (evaluateValue) {
var index = tokenized.length;
tokenized[index] = "';\n" + evaluateValue + ";\n__p += '";
return token + index;
}
return escapeValue
? tokenizeEscape(null, escapeValue)
: tokenizeInterpolate(null, interpolateValue);
}
/**
* Used by `template` to replace "interpolate" template delimiters with tokens.
*
* @private
* @param {String} match The matched template delimiter.
* @param {String} value The delimiter value.
* @returns {String} Returns a token.
*/
function tokenizeInterpolate(match, value) {
if (match && reComplexDelimiter.test(value)) {
return '<e%=' + value + '%>';
}
var index = tokenized.length;
tokenized[index] = "' +\n((__t = (" + value + ")) == null ? '' : __t) +\n'";
return token + index;
}
/*--------------------------------------------------------------------------*/
/**
* Checks if `value` is an `arguments` object.
*
* @static
* @memberOf _
* @category Objects
* @param {Mixed} value The value to check.
* @returns {Boolean} Returns `true` if the `value` is an `arguments` object, else `false`.
* @example
*
* (function() { return _.isArguments(arguments); })(1, 2, 3);
* // => true
*
* _.isArguments([1, 2, 3]);
* // => false
*/
function isArguments(value) {
return toString.call(value) == argsClass;
}
// fallback for browsers that can't detect `arguments` objects by [[Class]]
if (noArgsClass) {
isArguments = function(value) {
return !!(value && hasOwnProperty.call(value, 'callee'));
};
}
/**
* Checks if `value` is an array.
*
* @static
* @memberOf _
* @category Objects
* @param {Mixed} value The value to check.
* @returns {Boolean} Returns `true` if the `value` is an array, else `false`.
* @example
*
* (function() { return _.isArray(arguments); })();
* // => false
*
* _.isArray([1, 2, 3]);
* // => true
*/
var isArray = nativeIsArray || function(value) {
return toString.call(value) == arrayClass;
};
/**
* Checks if `value` is a function.
*
* @static
* @memberOf _
* @category Objects
* @param {Mixed} value The value to check.
* @returns {Boolean} Returns `true` if the `value` is a function, else `false`.
* @example
*
* _.isFunction(''.concat);
* // => true
*/
function isFunction(value) {
return typeof value == 'function';
}
// fallback for older versions of Chrome and Safari
if (isFunction(/x/)) {
isFunction = function(value) {
return toString.call(value) == funcClass;
};
}
/**
* A shim implementation of `Object.keys` that produces an array of the given
* object's own enumerable property names.
*
* @private
* @param {Object} object The object to inspect.
* @returns {Array} Returns a new array of property names.
*/
var shimKeys = createIterator({
'args': 'object',
'init': '[]',
'inLoop': 'result.push(index)'
});
/*--------------------------------------------------------------------------*/
/**
* Creates a clone of `value`. If `deep` is `true`, all nested objects will
* also be cloned otherwise they will be assigned by reference. If a value has
* a `clone` method it will be used to perform the clone. Functions, DOM nodes,
* `arguments` objects, and objects created by constructors other than `Object`
* are **not** cloned unless they have a custom `clone` method.
*
* @static
* @memberOf _
* @category Objects
* @param {Mixed} value The value to clone.
* @param {Boolean} deep A flag to indicate a deep clone.
* @param {Object} [guard] Internally used to allow this method to work with
* others like `_.map` without using their callback `index` argument for `deep`.
* @param {Array} [stack=[]] Internally used to keep track of traversed objects
* to avoid circular references.
* @param {Object} thorough Internally used to indicate whether or not to perform
* a more thorough clone of non-object values.
* @returns {Mixed} Returns the cloned `value`.
* @example
*
* var stooges = [
* { 'name': 'moe', 'age': 40 },
* { 'name': 'larry', 'age': 50 },
* { 'name': 'curly', 'age': 60 }
* ];
*
* _.clone({ 'name': 'moe' });
* // => { 'name': 'moe' }
*
* var shallow = _.clone(stooges);
* shallow[0] === stooges[0];
* // => true
*
* var deep = _.clone(stooges, true);
* shallow[0] === stooges[0];
* // => false
*/
function clone(value, deep, guard, stack, thorough) {
if (value == null) {
return value;
}
if (guard) {