/ajax/libs/lodash.js/1.0.0-rc.3/lodash.underscore.js

/*!
 * Lo-Dash 1.0.0-rc.3 (Custom Build) <http://lodash.com>
 * Build: `lodash underscore -d -o ./lodash.underscore.js`
 * (c) 2012 John-David Dalton <http://allyoucanleet.com/>
 * Based on Underscore.js 1.4.3 <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 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,
      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 various environments */
  var isIeOpera = !!window.attachEvent,
      isV8 = nativeBind && !/\n|true/.test(nativeBind + isIeOpera);

  /* Detect if `Function#bind` exists and is inferred to be fast (all but V8) */
  var isBindFast = nativeBind && !isV8;

  /**
   * 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 `arguments` objects are `Object` objects (all but Opera < 10.5) */
  var argsAreObjects = arguments.constructor == Object;

  /**
   * 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 sourceURL syntax is usable without erroring:
   *
   * The JS engine embedded in Adobe products 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('//@')(), !isIeOpera);
  } catch(e) { }

  /** 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'
  };

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

  /**
   * Creates a `lodash` object, that wraps the given `value`, to enable
   * method chaining.
   *
   * The chainable wrapper functions are:
   * `after`, `assign`, `bind`, `bindAll`, `bindKey`, `chain`, `compact`, `compose`,
   * `concat`, `countBy`, `debounce`, `defaults`, `defer`, `delay`, `difference`,
   * `filter`, `flatten`, `forEach`, `forIn`, `forOwn`, `functions`, `groupBy`,
   * `initial`, `intersection`, `invert`, `invoke`, `keys`, `map`, `max`, `memoize`,
   * `merge`, `min`, `object`, `omit`, `once`, `pairs`, `partial`, `pick`, `pluck`,
   * `push`, `range`, `reject`, `rest`, `reverse`, `shuffle`, `slice`, `sort`,
   * `sortBy`, `splice`, `tap`, `throttle`, `times`, `toArray`, `union`, `uniq`,
   * `unshift`, `values`, `where`, `without`, `wrap`, and `zip`
   *
   * The non-chainable wrapper functions are:
   * `clone`, `cloneDeep`, `contains`, `escape`, `every`, `find`, `has`, `identity`,
   * `indexOf`, `isArguments`, `isArray`, `isBoolean`, `isDate`, `isElement`, `isEmpty`,
   * `isEqual`, `isFinite`, `isFunction`, `isNaN`, `isNull`, `isNumber`, `isObject`,
   * `isPlainObject`, `isRegExp`, `isString`, `isUndefined`, `join`, `lastIndexOf`,
   * `mixin`, `noConflict`, `pop`, `random`, `reduce`, `reduceRight`, `result`,
   * `shift`, `size`, `some`, `sortedIndex`, `template`, `unescape`, and `uniqueId`
   *
   * The wrapper functions `first` and `last` return wrapped values when `n` is
   * passed, otherwise they return unwrapped values.
   *
   * @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, even if wrapped by a different `lodash` constructor
    if (value && typeof value == 'object' && 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': ''
  };

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

  /** 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] = iteratee[index]',
    'bottom': '  }\n}'
  };

  /**
   * Reusable iterator options shared by `each`, `forIn`, and `forOwn`.
   */
  var eachIteratorOptions = {
    'args': 'collection, callback, thisArg',
    'top': "callback = callback && typeof thisArg == 'undefined' ? callback : createCallback(callback, thisArg)",
    'arrayLoop': 'if (callback(iteratee[index], index, collection) === false) return result',
    'objectLoop': 'if (callback(iteratee[index], index, collection) === false) return result'
  };

  /** Reusable iterator options for `forIn` and `forOwn` */
  var forOwnIteratorOptions = {
    'arrayLoop': null
  };

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

  /**
   * 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 || typeof a == 'undefined') {
        return 1;
      }
      if (a < b || typeof 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) {
    function bound() {
      // `Function#bind` spec
      // http://es5.github.com/#x15.3.4.5
      var args = arguments,
          thisBinding = thisArg;

      if (partialArgs.length) {
        args = args.length
          ? partialArgs.concat(slice(args))
          : partialArgs;
      }
      if (this instanceof bound) {
        // ensure `new bound` is an instance of `bound` and `func`
        noop.prototype = func.prototype;
        thisBinding = new noop;
        noop.prototype = null;

        // 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`.
   * @param {Object} [accumulating] Used to indicate that the callback should
   *  accept an `accumulator` argument.
   * @returns {Function} Returns a callback function.
   */
  function createCallback(func, thisArg, accumulating) {
    if (!func) {
      return identity;
    }
    if (typeof func != 'function') {
      return function(object) {
        return object[func];
      };
    }
    if (typeof thisArg != 'undefined') {
      if (accumulating) {
        return function(accumulator, value, index, object) {
          return func.call(thisArg, accumulator, value, index, object);
        };
      }
      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,
      'objectLoop': '',
      'nonEnumArgs': nonEnumArgs,
      '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, isString, objectTypes, ' +
        'nativeKeys, propertyIsEnumerable',
      'return function(' + args + ') {\n' + (data) + '\n}'
    );
    // return the compiled function
    return factory(
      createCallback, hasOwnProperty, isString, objectTypes,
      nativeKeys, propertyIsEnumerable
    );
  }

  /**
   * A function compiled to iterate `arguments` objects, arrays, objects, and
   * strings consistenly across environments, executing the `callback` for each
   * element in the `collection`. The `callback` is bound to `thisArg` and invoked
   * with three arguments; (value, index|key, collection). Callbacks may exit
   * iteration early by explicitly returning `false`.
   *
   * @private
   * @param {Array|Object|String} collection The collection to iterate over.
   * @param {Function} [callback=identity] The function called per iteration.
   * @param {Mixed} [thisArg] The `this` binding of `callback`.
   * @returns {Array|Object|String} Returns `collection`.
   */
  var each = function (collection, callback, thisArg) {
    var index, iteratee = collection, result = collection;
    if (!collection) return result;
    callback = callback && typeof thisArg == 'undefined' ? callback : createCallback(callback, thisArg);
    var length = iteratee.length; index = -1;
    if (typeof length == 'number') {  
      while (++index < length) {
        if (callback(iteratee[index], index, collection) === indicatorObject) return result
      }
    }
    else {  
      for (index in iteratee) {
        if (hasOwnProperty.call(iteratee, index)) {    
        if (callback(iteratee[index], index, collection) === indicatorObject) return result;    
        }
      }    
    }
  };

  /**
   * 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];
  }

  /**
   * Checks if `value` is a DOM node in IE < 9.
   *
   * @private
   * @param {Mixed} value The value to check.
   * @returns {Boolean} Returns `true` if the `value` is a DOM node, else `false`.
   */
  function isNode(value) {
    // IE < 9 presents DOM nodes as `Object` objects except they have `toString`
    // methods that are `typeof` "string" and still can coerce nodes to strings
    return typeof value.toString != 'function' && typeof (value + '') == 'string';
  }

  /**
   * A no-operation function.
   *
   * @private
   */
  function noop() {
    // no operation performed
  }

  /**
   * Slices the `collection` from the `start` index up to, but not including,
   * the `end` index.
   *
   * Note: This function is used, instead of `Array#slice`, to support node lists
   * in IE < 9 and to ensure dense arrays are returned.
   *
   * @private
   * @param {Array|Object|String} collection The collection to slice.
   * @param {Number} start The start index.
   * @param {Number} end The end index.
   * @returns {Array} Returns the new array.
   */
  function slice(array, start, end) {
    start || (start = 0);
    if (typeof end == 'undefined') {
      end = array ? array.length : 0;
    }
    var index = -1,
        length = end - start || 0,
        result = Array(length < 0 ? 0 : length);

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

  /**
   * 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 }
   */
  function assign(object) {
    if (!object) {
      return object;
    }
    for (var argsIndex = 1, argsLength = arguments.length; argsIndex < argsLength; argsIndex++) {
      var iteratee = arguments[argsIndex];
      if (iteratee) {
        for (var key in iteratee) {
          object[key] = iteratee[key];
        }
      }
    }
    return object;
  }
  /**
   * 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
   */
  lodash.isArguments = function(value) {
    return toString.call(value) == argsClass;
  }

  // fallback for browsers that can't detect `arguments` objects by [[Class]]
  if (!lodash.isArguments(arguments)) {
    lodash.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=identity] 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 = function (collection, callback) {
    var index, iteratee = collection, result = collection;
    if (!collection) return result;
    callback || (callback = identity);
    
      for (index in iteratee) {
        if (callback(iteratee[index], index, collection) === indicatorObject) return result;    
      }    
    return result
  };

  /**
   * 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=identity] 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 = function (collection, callback) {
    var index, iteratee = collection, result = collection;
    if (!collection) return result;
    callback || (callback = identity);
    
      for (index in iteratee) {
        if (hasOwnProperty.call(iteratee, index)) {    
        if (callback(iteratee[index], index, collection) === indicatorObject) return result;    
        }
      }    
    return result
  };

  /**
   * 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;
    }
    // check that the constructor is `Object` (i.e. `Object instanceof Object`)
    var ctor = value.constructor;
    if ((!isFunction(ctor)) || ctor instanceof ctor) {
      // 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 = {
    '&': '&amp;',
    '<': '&lt;',
    '>': '&gt;',
    '"': '&quot;',
    "'": '&#x27;'
  };

  /** Used to convert HTML entities to characters */
  var htmlUnescapes = invert(htmlEscapes);

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

  /**
   * Creates a clone of `value`. If `deep` is `true`, nested objects will also
   * be cloned, otherwise they will be assigned by reference.
   *
   * @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 }
   * ];
   *
   * var shallow = _.clone(stooges);
   * shallow[0] === stooges[0];
   * // => true
   *
   * var deep = _.clone(stooges, true);
   * deep[0] === stooges[0];
   * // => false
   */
  function clone(value) {
    return value && objectTypes[typeof value]
      ? (isArray(value) ? slice(value) : assign({}, value))
      : value
  }

  /**
   * 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' }
   */
  function defaults(object) {
    if (!object) {
      return object;
    }
    for (var argsIndex = 1, argsLength = arguments.length; argsIndex < argsLength; argsIndex++) {
      var iteratee = arguments[argsIndex];
      if (iteratee) {
        for (var key in iteratee) {
          if (object[key] == null) {
            object[key] = iteratee[key];
          }
        }
      }
    }
    return object;
  }

  /**
   * Creates a sorted array of all enumerable properties, own and inherited,
   * of `object` that have function values.
   *
   * @static
   * @memberOf _
   * @alias methods
   * @category Objects
   * @param {Object} object The object to inspect.
   * @returns {Array} Returns a new array of property names that have function values.
   * @example
   *
   * _.functions(_);
   * // => ['all', 'any', 'bind', 'bindAll', 'clone', 'compact', 'compose', ...]
   */
  function functions(object) {
    var result = [];
    forIn(object, function(value, key) {
      if (isFunction(value)) {
        result.push(key);
      }
    });
    return result.sort();
  }

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

  /**
   * Creates an object composed of the inverted keys and values of the given `object`.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Object} object The object to invert.
   * @returns {Object} Returns the created inverted object.
   * @example
   *
   *  _.invert({ 'first': 'Moe', 'second': 'Larry', 'third': 'Curly' });
   * // => { 'Moe': 'first', 'Larry': 'second', 'Curly': 'third' } (order is not guaranteed)
   */
  function invert(object) {
    var result = {};
    forOwn(object, function(value, key) {
      result[value] = key;
    });
    return result;
  }

  /**
   * 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) {
    // `instanceof` may cause a memory leak in IE 7 if `value` is a host object
    // http://ajaxian.com/archives/working-aroung-the-instanceof-memory-leak
    return (argsAreObjects && value instanceof Array) || toString.call(value) == arrayClass;
  };

  /**
   * Checks if `value` is a boolean (`true` or `false`) value.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} value The value to check.
   * @returns {Boolean} Returns `true` if the `value` is a boolean value, else `false`.
   * @example
   *
   * _.isBoolean(null);
   * // => false
   */
  function isBoolean(value) {
    return value === true || value === false || toString.call(value) == boolClass;
  }

  /**
   * Checks if `value` is a date.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} value The value to check.
   * @returns {Boolean} Returns `true` if the `value` is a date, else `false`.
   * @example
   *
   * _.isDate(new Date);
   * // => true
   */
  function isDate(value) {
    return value instanceof Date || toString.call(value) == dateClass;
  }

  /**
   * Checks if `value` is a DOM element.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} value The value to check.
   * @returns {Boolean} Returns `true` if the `value` is a DOM element, else `false`.
   * @example
   *
   * _.isElement(document.body);
   * // => true
   */
  function isElement(value) {
    return value ? value.nodeType === 1 : false;
  }

  /**
   * Checks if `value` is empty. Arrays, strings, or `arguments` objects with a
   * length of `0` and objects with no own enumerable properties are considered
   * "empty".
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Array|Object|String} value The value to inspect.
   * @returns {Boolean} Returns `true` if the `value` is empty, else `false`.
   * @example
   *
   * _.isEmpty([1, 2, 3]);
   * // => false
   *
   * _.isEmpty({});
   * // => true
   *
   * _.isEmpty('');
   * // => true
   */
  function isEmpty(value) {
    if (!value) {
      return true;
    }
    if (isArray(value) || isString(value)) {
      return !value.length;
    }
    for (var key in value) {
      if (hasOwnProperty.call(value, key)) {
        return false;
      }
    }
    return true;
  }

  /**
   * Performs a deep comparison between two values to determine if they are
   * equivalent to each other.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} a The value to compare.
   * @param {Mixed} b The other value to compare.
   * @param- {Object} [stackA=[]] Internally used track traversed `a` objects.
   * @param- {Object} [stackB=[]] Internally used track traversed `b` objects.
   * @returns {Boolean} Returns `true` if the values are equvalent, else `false`.
   * @example
   *
   * var moe = { 'name': 'moe', 'luckyNumbers': [13, 27, 34] };
   * var clone = { 'name': 'moe', 'luckyNumbers': [13, 27, 34] };
   *
   * moe == clone;
   * // => false
   *
   * _.isEqual(moe, clone);
   * // => true
   */
  function isEqual(a, b, stackA, stackB) {
    // exit early for identical values
    if (a === b) {
      // treat `+0` vs. `-0` as not equal
      return a !== 0 || (1 / a == 1 / b);
    }
    // a strict comparison is necessary because `null == undefined`
    if (a == null || b == null) {
      return a === b;
    }
    // compare [[Class]] names
    var className = toString.call(a),
        otherName = toString.call(b);

    if (className != otherName) {
      return false;
    }
    switch (className) {
      case boolClass:
      case dateClass:
        // coerce dates and booleans to numbers, dates to milliseconds and booleans
        // to `1` or `0`, treating invalid dates coerced to `NaN` as not equal
        return +a == +b;

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

      case regexpClass:
      case stringClass:
        // coerce regexes to strings (http://es5.github.com/#x15.10.6.4)
        // treat string primitives and their corresponding object instances as equal
        return a == b + '';
    }
    var isArr = className == arrayClass;
    if (!isArr) {
      // unwrap any `lodash` wrapped values
      if (a.__wrapped__ || b.__wrapped__) {
        return isEqual(a.__wrapped__ || a, b.__wrapped__ || b);
      }
      // exit for functions and DOM nodes
      if (className != objectClass) {
        return false;
      }
      // in older versions of Opera, `arguments` objects have `Array` constructors
      var ctorA = a.constructor,
          ctorB = b.constructor;

      // non `Object` object instances with different constructors are not equal
      if (ctorA != ctorB && !(
            isFunction(ctorA) && ctorA instanceof ctorA &&
            isFunction(ctorB) && ctorB instanceof ctorB
          )) {
        return false;
      }
    }
    // assume cyclic structures are equal
    // the algorithm for detecting cyclic structures is adapted from ES 5.1
    // section 15.12.3, abstract operation `JO` (http://es5.github.com/#x15.12.3)
    stackA || (stackA = []);
    stackB || (stackB = []);

    var length = stackA.length;
    while (length--) {
      if (stackA[length] == a) {
        return stackB[length] == b;
      }
    }
    var index = -1,
        result = true,
        size = 0;

    // add `a` and `b` to the stack of traversed objects
    stackA.push(a);
    stackB.push(b);

    // recursively compare objects and arrays (susceptible to call stack limits)
    if (isArr) {
      // compare lengths to determine if a deep comparison is necessary
      size = a.length;
      result = size == b.length;

      if (result) {
        // deep compare the contents, ignoring non-numeric properties
        while (size--) {
          if (!(result = isEqual(a[size], b[size], stackA, stackB))) {
            break;
          }
        }
      }
      return result;
    }
    // deep compare objects using `forIn`, instead of `forOwn`, to avoid `Object.keys`
    // which, in this case, is more costly
    forIn(a, function(value, key, a) {
      if (hasOwnProperty.call(a, key)) {
        // count the number of properties.
        size++;
        // deep compare each property value.
        return !(result = hasOwnProperty.call(b, key) && isEqual(value, b[key], stackA, stackB)) && indicatorObject;
      }
    });

    if (result) {
      // ensure both objects have the same number of properties
      forIn(b, function(value, key, b) {
        if (hasOwnProperty.call(b, key)) {
          // `size` will be `-1` if `b` has more properties than `a`
          return !(result = --size > -1) && indicatorObject;
        }
      });
    }
    return result;
  }

  /**
   * Checks if `value` is, or can be coerced to, a finite number.
   *
   * Note: This is not the same as native `isFinite`, which will return true for
   * booleans and empty strings. See http://es5.github.com/#x15.1.2.5.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} value The value to check.
   * @returns {Boolean} Returns `true` if the `value` is a finite number, else `false`.
   * @example
   *
   * _.isFinite(-101);
   * // => true
   *
   * _.isFinite('10');
   * // => true
   *
   * _.isFinite(true);
   * // => false
   *
   * _.isFinite('');
   * // => false
   *
   * _.isFinite(Infinity);
   * // => false
   */
  function isFinite(value) {
    return nativeIsFinite(value) && !nativeIsNaN(parseFloat(value));
  }

  /**
   * 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(_);
   * // => true
   */
  function isFunction(value) {
    return typeof value == 'function';
  }
  // fallback for older versions of Chrome and Safari
  if (isFunction(/x/)) {
    isFunction = function(value) {
      return value instanceof Function || toString.call(value) == funcClass;
    };
  }

  /**
   * Checks if `value` is the language type of Object.
   * (e.g. arrays, functions, objects, regexes, `new Number(0)`, and `new String('')`)
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} value The value to check.
   * @returns {Boolean} Returns `true` if the `value` is an object, else `false`.
   * @example
   *
   * _.isObject({});
   * // => true
   *
   * _.isObject([1, 2, 3]);
   * // => true
   *
   * _.isObject(1);
   * // => false
   */
  function isObject(value) {
    // check if the value is the ECMAScript language type of Object
    // http://es5.github.com/#x8
    // and avoid a V8 bug
    // http://code.google.com/p/v8/issues/detail?id=2291
    return value ? objectTypes[typeof value] : false;
  }

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

  /**
   * Checks if `value` is `null`.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} value The value to check.
   * @returns {Boolean} Returns `true` if the `value` is `null`, else `false`.
   * @example
   *
   * _.isNull(null);
   * // => true
   *
   * _.isNull(undefined);
   * // => false
   */
  function isNull(value) {
    return value === null;
  }

  /**
   * Checks if `value` is a number.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} value The value to check.
   * @returns {Boolean} Returns `true` if the `value` is a number, else `false`.
   * @example
   *
   * _.isNumber(8.4 * 5);
   * // => true
   */
  function isNumber(value) {
    return typeof value == 'number' || toString.call(value) == numberClass;
  }

  /**
   * Checks if `value` is a regular expression.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} value The value to check.
   * @returns {Boolean} Returns `true` if the `value` is a regular expression, else `false`.
   * @example
   *
   * _.isRegExp(/moe/);
   * // => true
   */
  function isRegExp(value) {
    return value instanceof RegExp || toString.call(value) == regexpClass;
  }

  /**
   * Checks if `value` is a string.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Mixed} value The value to check.
   * @returns {Boolean} Returns `true` if the `value` is a string, else `false`.
   * @example
   *
   * _.isString('moe');
   * // => true
   */
  function isString(value) {
    return typeof value == 'string' || toString.call(value) == stringClass;
  }

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

  /**
   * Creates an array composed of the own enumerable property names of `object`.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Object} object The object to inspect.
   * @returns {Array} Returns a new array of property names.
   * @example
   *
   * _.keys({ 'one': 1, 'two': 2, 'three': 3 });
   * // => ['one', 'two', 'three'] (order is not guaranteed)
   */
  var keys = !nativeKeys ? shimKeys : function(object) {
    return (isObject(object) ? nativeKeys(object) : []);
  };

  /**
   * Creates a shallow clone of `object` excluding the specified properties.
   * Property names may be specified as individual arguments or as arrays of
   * property names. If `callback` is passed, it will be executed for each property
   * in the `object`, omitting the properties `callback` returns truthy for. The
   * `callback` is bound to `thisArg` and invoked with three arguments; (value, key, object).
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Object} object The source object.
   * @param {Function|String} callback|[prop1, prop2, ...] The properties to omit
   *  or the function called per iteration.
   * @param {Mixed} [thisArg] The `this` binding of `callback`.
   * @returns {Object} Returns an object without the omitted properties.
   * @example
   *
   * _.omit({ 'name': 'moe', 'age': 40, 'userid': 'moe1' }, 'userid');
   * // => { 'name': 'moe', 'age': 40 }
   *
   * _.omit({ 'name': 'moe', '_hint': 'knucklehead', '_seed': '96c4eb' }, function(value, key) {
   *   return key.charAt(0) == '_';
   * });
   * // => { 'name': 'moe' }
   */
  function omit(object) {
    var props = concat.apply(arrayRef, arguments),
        result = {};

    forIn(object, function(value, key) {
      if (indexOf(props, key, 1) < 0) {
        result[key] = value;
      }
    });
    return result;
  }

  /**
   * Creates a two dimensional array of the given object's key-value pairs,
   * i.e. `[[key1, value1], [key2, value2]]`.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Object} object The object to inspect.
   * @returns {Array} Returns new array of key-value pairs.
   * @example
   *
   * _.pairs({ 'moe': 30, 'larry': 40, 'curly': 50 });
   * // => [['moe', 30], ['larry', 40], ['curly', 50]] (order is not guaranteed)
   */
  function pairs(object) {
    var result = [];
    forOwn(object, function(value, key) {
      result.push([key, value]);
    });
    return result;
  }

  /**
   * Creates a shallow clone of `object` composed of the specified properties.
   * Property names may be specified as individual arguments or as arrays of
   * property names. If `callback` is passed, it will be executed for each property
   * in the `object`, picking the properties `callback` returns truthy for. The
   * `callback` is bound to `thisArg` and invoked with three arguments; (value, key, object).
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Object} object The source object.
   * @param {Function|String} callback|[prop1, prop2, ...] The properties to pick
   *  or the function called per iteration.
   * @param {Mixed} [thisArg] The `this` binding of `callback`.
   * @returns {Object} Returns an object composed of the picked properties.
   * @example
   *
   * _.pick({ 'name': 'moe', 'age': 40, 'userid': 'moe1' }, 'name', 'age');
   * // => { 'name': 'moe', 'age': 40 }
   *
   * _.pick({ 'name': 'moe', '_hint': 'knucklehead', '_seed': '96c4eb' }, function(value, key) {
   *   return key.charAt(0) != '_';
   * });
   * // => { 'name': 'moe' }
   */
  function pick(object) {
    var index = 0,
        props = concat.apply(arrayRef, arguments),
        length = props.length,
        result = {};

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

  /**
   * Creates an array composed of the own enumerable property values of `object`.
   *
   * @static
   * @memberOf _
   * @category Objects
   * @param {Object} object The object to inspect.
   * @returns {Array} Returns a new array of property values.
   * @example
   *
   * _.values({ 'one': 1, 'two': 2, 'three': 3 });
   * // => [1, 2, 3]
   */
  function values(object) {
    var result = [];
    forOwn(object, function(value) {
      result.push(value);
    });
    return result;
  }

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

  /**
   * Checks if a given `target` element is present in a `collection` using strict
   * equality for comparisons, i.e. `===`. If `fromIndex` is negative, it is used
   * as the offset from the end of the collection.
   *
   * @static
   * @memberOf _
   * @alias include
   * @category Collections
   * @param {Array|Object|String} collection The collection to iterate over.
   * @param {Mixed} target The value to check for.
   * @param {Number} [fromIndex=0] The index to search from.
   * @returns {Boolean} Returns `true` if the `target` element is found, else `false`.
   * @example
   *
   * _.contains([1, 2, 3], 1);
   * // => true
   *
   * _.contains([1, 2, 3], 1, 2);
   * // => false
   *
   * _.contains({ 'name': 'moe', 'age': 40 }, 'moe');
   * // => true
   *
   * _.contains('curly', 'ur');
   * // => true
   */
  function contains(collection, target) {
    var length = collection ? collection.length : 0,
        result = false;
    if (typeof length == 'number') {
      result = indexOf(collection, target) > -1;
    } else {
      each(collection, function(value) {
        return (result = value === target) && indicatorObject;
      });
    }
    return result;
  }

  /**
   * Creates an object composed of keys returned from running each element of
   * `collection` through a `callback`. The corresponding value of each key is
   * the number of times the key was returned by `callback`. The `callback` is
   * bound to `thisArg` and invoked with three arguments; (value, index|key, collection).
   * The `callback` argument may also be the name of a property to count by (e.g. 'length').
   *
   * @static
   * @memberOf _
   * @category Collections
   * @param {Array|Object|String} collection The collection to iterate over.
   * @param {Function|String} callback|property The function called per iteration
   *  or property name to count by.
   * @param {Mixed} [thisArg] The `this` binding of `callback`.
   * @returns {Object} Returns the composed aggregate object.
   * @example
   *
   * _.countBy([4.3, 6.1, 6.4], function(num) { return Math.floor(num); });
   * // => { '4': 1, '6': 2 }
   *
   * _.countBy([4.3, 6.1, 6.4], function(num) { return this.floor(num); }, Math);
   * // => { '4': 1, '6': 2 }
   *
   * _.countBy(['one', 'two', 'three'], 'length');
   * // => { '3': 2, '5': 1 }
   */
  function countBy(collection, callback, thisArg) {
    var result = {};
    callback = createCallback(callback, thisArg);

    forEach(collection, function(value, key, collection) {
      key = callback(value, key, collection);
      (hasOwnProperty.call(result, key) ? result[key]++ : result[key] = 1);
    });
    return result;
  }

  /**
   * Checks if the `callback` returns a truthy value for **all** elements of a
   * `collection`. The `callback` is bound to `thisArg` and invoked with three
   * arguments; (value, index|k