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lodash.js
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/*!
* Lo-Dash 0.9.2 <http://lodash.com>
* (c) 2012 John-David Dalton <http://allyoucanleet.com/>
* Based on Underscore.js 1.4.2 <http://underscorejs.org>
* (c) 2009-2012 Jeremy Ashkenas, DocumentCloud Inc.
* Available under MIT license <http://lodash.com/license>
*/
;(function(window, undefined) {
/** Detect free variable `exports` */
var freeExports = typeof exports == 'object' && exports;
/** Detect free variable `global` and use it as `window` */
var freeGlobal = typeof global == 'object' && global;
if (freeGlobal.global === freeGlobal) {
window = freeGlobal;
}
/** Used for array and object method references */
var arrayRef = [],
// avoid a Closure Compiler bug by creatively creating an object
objectRef = new function(){};
/** Used to generate unique IDs */
var idCounter = 0;
/** Used internally to indicate various things */
var indicatorObject = objectRef;
/** Used by `cachedContains` as the default size when optimizations are enabled for large arrays */
var largeArraySize = 30;
/** Used to restore the original `_` reference in `noConflict` */
var oldDash = window._;
/** Used to detect template delimiter values that require a with-statement */
var reComplexDelimiter = /[-?+=!~*%&^<>|{(\/]|\[\D|\b(?:delete|in|instanceof|new|typeof|void)\b/;
/** Used to match HTML entities */
var reEscapedHtml = /&(?:amp|lt|gt|quot|#x27);/g;
/** 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('^' +
(objectRef.valueOf + '')
.replace(/[.*+?^=!:${}()|[\]\/\\]/g, '\\$&')
.replace(/valueOf|for [^\]]+/g, '.+?') + '$'
);
/**
* Used to match ES6 template delimiters
* http://people.mozilla.org/~jorendorff/es6-draft.html#sec-7.8.6
*/
var reEsTemplate = /\$\{((?:(?=\\?)\\?[\s\S])*?)}/g;
/** Used to match "interpolate" template delimiters */
var reInterpolate = /<%=([\s\S]+?)%>/g;
/** Used to ensure capturing order of template delimiters */
var reNoMatch = /($^)/;
/** Used to match HTML characters */
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;
/** Native method shortcuts */
var ceil = Math.ceil,
concat = arrayRef.concat,
floor = Math.floor,
getPrototypeOf = reNative.test(getPrototypeOf = Object.getPrototypeOf) && getPrototypeOf,
hasOwnProperty = objectRef.hasOwnProperty,
push = arrayRef.push,
propertyIsEnumerable = objectRef.propertyIsEnumerable,
slice = arrayRef.slice,
toString = objectRef.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,
nativeIsNaN = window.isNaN,
nativeKeys = reNative.test(nativeKeys = Object.keys) && nativeKeys,
nativeMax = Math.max,
nativeMin = Math.min,
nativeRandom = Math.random;
/** `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]';
/**
* 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 `Array#shift` and `Array#splice` augment array-like objects
* incorrectly:
*
* Firefox < 10, IE compatibility mode, and IE < 9 have buggy Array `shift()`
* and `splice()` functions that fail to remove the last element, `value[0]`,
* of array-like objects even though the `length` property is set to `0`.
* The `shift()` method is buggy in IE 8 compatibility mode, while `splice()`
* is buggy regardless of mode in IE < 9 and buggy in compatibility mode in IE 9.
*/
var hasObjectSpliceBug = (hasObjectSpliceBug = { '0': 1, 'length': 1 },
arrayRef.splice.call(hasObjectSpliceBug, 0, 1), hasObjectSpliceBug[0]);
/** 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 = !/valueOf/.test(props);
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 sourceURL syntax is usable without erroring:
*
* 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.
*
* Avoid comments beginning `@` symbols in IE because they are part of its
* non-standard conditional compilation support.
* http://msdn.microsoft.com/en-us/library/121hztk3(v=vs.94).aspx
*/
try {
var useSourceURL = (Function('//@')(), !window.attachEvent);
} catch(e) { }
/** 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 determine if values are of the language type Object */
var objectTypes = {
'boolean': false,
'function': true,
'object': true,
'number': false,
'string': false,
'undefined': false
};
/** 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
* @category Chaining
* @param {Mixed} value The value to wrap in a `lodash` instance.
* @returns {Object} Returns a `lodash` instance.
*/
function lodash(value) {
// exit early if already wrapped
if (value && value.__wrapped__) {
return value;
}
// allow invoking `lodash` without the `new` operator
if (!(this instanceof lodash)) {
return new lodash(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': reInterpolate,
/**
* 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 (obj.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 = <%= firstArg %>;\n' +
// exit early if the first argument is falsey
'if (!<%= firstArg %>) return result;\n' +
// add code before the iteration branches
'<%= top %>;\n' +
// array-like iteration:
'<% if (arrayLoop) { %>' +
'var length = iteratee.length; index = -1;\n' +
'if (typeof length == \'number\') {' +
// add support for accessing string characters by index if needed
' <% if (noCharByIndex) { %>\n' +
' if (isString(iteratee)) {\n' +
' iteratee = iteratee.split(\'\')\n' +
' }' +
' <% } %>\n' +
// iterate over the array-like value
' while (++index < length) {\n' +
' value = iteratee[index];\n' +
' <%= arrayLoop %>\n' +
' }\n' +
'}\n' +
'else {' +
// object iteration:
// 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' +
' <%= objectLoop %>\n' +
' }\n' +
' } else {' +
' <% } %>' +
// 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.
' <% 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' +
' while (++ownIndex < length) {\n' +
' index = ownProps[ownIndex];\n' +
' <% if (!hasDontEnumBug) { %>if (!(skipProto && index == \'prototype\')) {\n <% } %>' +
' value = iteratee[index];\n' +
' <%= objectLoop %>\n' +
' <% if (!hasDontEnumBug) { %>}\n<% } %>' +
' }' +
// else using a for-in loop
' <% } else { %>\n' +
' for (index in iteratee) {<%' +
' if (!hasDontEnumBug || useHas) { %>\n if (<%' +
' if (!hasDontEnumBug) { %>!(skipProto && index == \'prototype\')<% }' +
' if (!hasDontEnumBug && useHas) { %> && <% }' +
' if (useHas) { %>hasOwnProperty.call(iteratee, index)<% }' +
' %>) {' +
' <% } %>\n' +
' value = iteratee[index];\n' +
' <%= objectLoop %>;' +
' <% if (!hasDontEnumBug || useHas) { %>\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' +
' <%= objectLoop %>\n' +
' }' +
' <% } %>' +
' <% } %>' +
' <% if (arrayLoop || noArgsEnum) { %>\n}<% } %>\n' +
// add code to the bottom of the iteration function
'<%= bottom %>;\n' +
// finally, return the `result`
'return result'
);
/** Reusable iterator options for `assign` and `defaults` */
var assignIteratorOptions = {
'args': 'object, source, guard',
'top':
'for (var argsIndex = 1, argsLength = typeof guard == \'number\' ? 2 : arguments.length; argsIndex < argsLength; argsIndex++) {\n' +
' if ((iteratee = arguments[argsIndex])) {',
'objectLoop': 'result[index] = value',
'bottom': ' }\n}'
};
/**
* Reusable iterator options shared by `forEach`, `forIn`, and `forOwn`.
*/
var forEachIteratorOptions = {
'args': 'collection, callback, thisArg',
'top': 'callback = createCallback(callback, thisArg)',
'arrayLoop': 'if (callback(value, index, collection) === false) return result',
'objectLoop': 'if (callback(value, index, collection) === false) return result'
};
/** Reusable iterator options for `forIn` and `forOwn` */
var forOwnIteratorOptions = {
'arrayLoop': null
};
/*--------------------------------------------------------------------------*/
/**
* Creates a function optimized to search 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 search 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 || largeArraySize);
if (isLarge) {
var cache = {},
index = fromIndex - 1;
while (++index < length) {
// manually coerce `value` to a string because `hasOwnProperty`, in some
// older versions of Firefox, coerces objects incorrectly
var 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(array, value, fromIndex) > -1;
}
}
/**
* Used by `_.max` and `_.min` as the default `callback` when a given
* `collection` is a string value.
*
* @private
* @param {String} value The character to inspect.
* @returns {Number} Returns the code unit of given character.
*/
function charAtCallback(value) {
return value.charCodeAt(0);
}
/**
* 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;
// ensure a stable sort in V8 and other engines
// http://code.google.com/p/v8/issues/detail?id=90
if (a !== b) {
if (a > b || a === undefined) {
return 1;
}
if (a < b || b === undefined) {
return -1;
}
}
return ai < bi ? -1 : 1;
}
/**
* Creates a function that, when called, invokes `func` with the `this`
* binding of `thisArg` and prepends any `partailArgs` to the arguments passed
* to the bound function.
*
* @private
* @param {Function|String} func The function to bind or the method name.
* @param {Mixed} [thisArg] The `this` binding of `func`.
* @param {Array} partialArgs An array of arguments to be partially applied.
* @returns {Function} Returns the new bound function.
*/
function createBound(func, thisArg, partialArgs) {
var isFunc = isFunction(func),
isPartial = !partialArgs,
methodName = func;
// juggle arguments
if (isPartial) {
partialArgs = thisArg;
}
function bound() {
// `Function#bind` spec
// http://es5.github.com/#x15.3.4.5
var args = arguments,
thisBinding = isPartial ? this : thisArg;
if (!isFunc) {
func = thisArg[methodName];
}
if (partialArgs.length) {
args = args.length
? partialArgs.concat(slice.call(args))
: partialArgs;
}
if (this instanceof bound) {
// get `func` instance if `bound` is invoked in a `new` expression
noop.prototype = func.prototype;
thisBinding = new noop;
// mimic the constructor's `return` behavior
// http://es5.github.com/#x13.2.2
var result = func.apply(thisBinding, args);
return isObject(result)
? result
: thisBinding
}
return func.apply(thisBinding, args);
}
return bound;
}
/**
* Produces an iteration callback bound to an optional `thisArg`. If `func` is
* a property name, the callback will return the property value for a given element.
*
* @private
* @param {Function|String} [func=identity|property] The function called per
* iteration or property name to query.
* @param {Mixed} [thisArg] The `this` binding of `callback`.
* @returns {Function} Returns a callback function.
*/
function createCallback(func, thisArg) {
if (!func) {
return identity;
}
if (typeof func != 'function') {
return function(object) {
return object[func];
};
}
if (thisArg !== undefined) {
return function(value, index, object) {
return func.call(thisArg, value, index, object);
};
}
return func;
}
/**
* Creates compiled iteration functions.
*
* @private
* @param {Object} [options1, options2, ...] The compile options object(s).
* useHas - A boolean to specify using `hasOwnProperty` checks in the object loop.
* args - A string of comma separated arguments the iteration function will accept.
* top - A string of code to execute before the iteration branches.
* arrayLoop - A string of code to execute in the array loop.
* objectLoop - A string of code to execute in the object loop.
* bottom - A string of code to execute after the iteration branches.
*
* @returns {Function} Returns the compiled function.
*/
function createIterator() {
var data = {
'arrayLoop': '',
'bottom': '',
'hasDontEnumBug': hasDontEnumBug,
'isKeysFast': isKeysFast,
'objectLoop': '',
'noArgsEnum': noArgsEnum,
'noCharByIndex': noCharByIndex,
'shadowed': shadowed,
'top': '',
'useHas': true
};
// merge options into a template data object
for (var object, index = 0; object = arguments[index]; index++) {
for (var key in object) {
data[key] = object[key];
}
}
var args = data.args;
data.firstArg = /^[^,]+/.exec(args)[0];
// create the function factory
var factory = Function(
'createCallback, hasOwnProperty, isArguments, isString, objectTypes, ' +
'nativeKeys, propertyIsEnumerable',
'return function(' + args + ') {\n' + iteratorTemplate(data) + '\n}'
);
// return the compiled function
return factory(
createCallback, hasOwnProperty, isArguments, isString, objectTypes,
nativeKeys, propertyIsEnumerable
);
}
/**
* 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 convert characters to HTML entities.
*
* @private
* @param {String} match The matched character to escape.
* @returns {String} Returns the escaped character.
*/
function escapeHtmlChar(match) {
return htmlEscapes[match];
}
/**
* A no-operation function.
*
* @private
*/
function noop() {
// no operation performed
}
/**
* Used by `unescape` to convert HTML entities to characters.
*
* @private
* @param {String} match The matched character to unescape.
* @returns {String} Returns the unescaped character.
*/
function unescapeHtmlChar(match) {
return htmlUnescapes[match];
}
/*--------------------------------------------------------------------------*/
/**
* Assigns own enumerable properties of source object(s) to the `destination`
* object. Subsequent sources will overwrite propery assignments of previous
* sources.
*
* @static
* @memberOf _
* @alias extend
* @category Objects
* @param {Object} object The destination object.
* @param {Object} [source1, source2, ...] The source objects.
* @returns {Object} Returns the destination object.
* @example
*
* _.assign({ 'name': 'moe' }, { 'age': 40 });
* // => { 'name': 'moe', 'age': 40 }
*/
var assign = createIterator(assignIteratorOptions);
/**
* 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') : false;
};
}
/**
* Iterates over `object`'s own and inherited enumerable properties, executing
* the `callback` for each property. The `callback` is bound to `thisArg` and
* invoked with three arguments; (value, key, object). Callbacks may exit iteration
* early by explicitly returning `false`.
*
* @static
* @memberOf _
* @category Objects
* @param {Object} object The object to iterate over.
* @param {Function} callback The function called per iteration.
* @param {Mixed} [thisArg] The `this` binding of `callback`.
* @returns {Object} Returns `object`.
* @example
*
* function Dog(name) {
* this.name = name;
* }
*
* Dog.prototype.bark = function() {
* alert('Woof, woof!');
* };
*
* _.forIn(new Dog('Dagny'), function(value, key) {
* alert(key);
* });
* // => alerts 'name' and 'bark' (order is not guaranteed)
*/
var forIn = createIterator(forEachIteratorOptions, forOwnIteratorOptions, {
'useHas': false
});
/**
* Iterates over an object's own enumerable properties, executing the `callback`
* for each property. The `callback` is bound to `thisArg` and invoked with three
* arguments; (value, key, object). Callbacks may exit iteration early by explicitly
* returning `false`.
*
* @static
* @memberOf _
* @category Objects
* @param {Object} object The object to iterate over.
* @param {Function} callback The function called per iteration.
* @param {Mixed} [thisArg] The `this` binding of `callback`.
* @returns {Object} Returns `object`.
* @example
*
* _.forOwn({ '0': 'zero', '1': 'one', 'length': 2 }, function(num, key) {
* alert(key);
* });
* // => alerts '0', '1', and 'length' (order is not guaranteed)
*/
var forOwn = createIterator(forEachIteratorOptions, forOwnIteratorOptions);
/**
* A fallback implementation of `isPlainObject` that 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.
* @returns {Boolean} Returns `true` if `value` is a plain object, else `false`.
*/
function shimIsPlainObject(value) {
// avoid non-objects and false positives for `arguments` objects
var result = false;
if (!(value && typeof value == 'object') || 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(value, key, object) {
result = !hasOwnProperty.call(object, key);
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(value, key) {
result = key;
});
return result === false || hasOwnProperty.call(value, result);
}
return result;
}
/**
* A fallback 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.
*/
function shimKeys(object) {
var result = [];
forOwn(object, function(value, key) {
result.push(key);
});
return result;
}
/**
* Used to convert characters to HTML entities:
*
* 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 an unquoted attribute value.
* http://mathiasbynens.be/notes/ambiguous-ampersands (under "semi-related fun fact")
*/
var htmlEscapes = {
'&': '&',
'<': '<',
'>': '>',
'"': '"',
"'": '''
};
/** Used to convert HTML entities to characters */
var htmlUnescapes = invert(htmlEscapes);
/*--------------------------------------------------------------------------*/
/**
* Creates a clone of `value`. If `deep` is `true`, all nested objects will
* also be cloned otherwise they will be assigned by reference. Functions, DOM
* nodes, `arguments` objects, and objects created by constructors other than
* `Object` are **not** cloned.
*
* @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} [stackA=[]] Internally used to track traversed source objects.
* @param- {Array} [stackB=[]] Internally used to associate clones with their
* source counterparts.
* @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, stackA, stackB) {
if (value == null) {
return value;
}
if (guard) {
deep = false;
}
// inspect [[Class]]
var isObj = isObject(value);
if (isObj) {
// don't clone `arguments` objects, functions, or non-object Objects
var className = toString.call(value);
if (!cloneableClasses[className] || (noArgsClass && isArguments(value))) {
return value;
}
var isArr = className == arrayClass;
isObj = isArr || (className == objectClass ? isPlainObject(value) : isObj);
}
// shallow clone
if (!isObj || !deep) {
// don't clone functions
return isObj
? (isArr ? slice.call(value) : assign({}, value))
: value;
}
var ctor = value.constructor;
switch (className) {
case boolClass:
case dateClass:
return new ctor(+value);
case numberClass:
case stringClass:
return new ctor(value);
case regexpClass:
return ctor(value.source, reFlags.exec(value));
}
// 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];
}
}
// init cloned object
var result = isArr ? ctor(value.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 ? forEach : forOwn)(value, function(objValue, key) {
result[key] = clone(objValue, deep, null, stackA, stackB);
});
return result;
}
/**
* Assigns own enumerable properties of source object(s) to the `destination`
* object for all `destination` properties that resolve to `null`/`undefined`.
* Once a property is set, additional defaults of the same property will be
* ignored.
*
* @static
* @memberOf _
* @category Objects
* @param {Object} object The destination object.
* @param {Object} [default1, default2, ...] The default objects.
* @returns {Object} Returns the destination object.
* @example
*
* var iceCream = { 'flavor': 'chocolate' };
* _.defaults(iceCream, { 'flavor': 'vanilla', 'sprinkles': 'rainbow' });
* // => { 'flavor': 'chocolate', 'sprinkles': 'rainbow' }
*/
var defaults = createIterator(assignIteratorOptions, {
'objectLoop': 'if (result[index] == null) ' + assignIteratorOptions.objectLoop
});