Bump to v3.7.0.

README.md

@@ -1,4 +1,4 @@
-# lodash v3.6.0
+# lodash v3.7.0
 
 The [modern build](https://github.com/lodash/lodash/wiki/Build-Differences) of [lodash](https://lodash.com/) exported as [AMD](https://github.com/amdjs/amdjs-api/wiki/AMD) modules.
 
@@ -10,6 +10,13 @@ $ lodash modern exports=amd -d -o ./main.js
 
 ## Installation
 
+Using bower or volo:
+
+```bash
+$ bower i lodash#3.7.0-amd
+$ volo add lodash/3.7.0-amd
+```
+
 Defining a build as `'lodash'`.
 
 ```js

array/intersection.js

@@ -23,7 +23,8 @@ define(['../internal/baseIndexOf', '../internal/cacheIndexOf', '../internal/crea
         argsLength = arguments.length,
         caches = [],
         indexOf = baseIndexOf,
-        isCommon = true;
+        isCommon = true,
+        result = [];
 
     while (++argsIndex < argsLength) {
       var value = arguments[argsIndex];
@@ -33,10 +34,12 @@ define(['../internal/baseIndexOf', '../internal/cacheIndexOf', '../internal/crea
       }
     }
     argsLength = args.length;
+    if (argsLength < 2) {
+      return result;
+    }
     var array = args[0],
         index = -1,
         length = array ? array.length : 0,
-        result = [],
         seen = caches[0];
 
     outer:

array/pullAt.js

@@ -1,10 +1,4 @@
-define(['../internal/baseAt', '../internal/baseCompareAscending', '../internal/baseFlatten', '../internal/isIndex', '../function/restParam'], function(baseAt, baseCompareAscending, baseFlatten, isIndex, restParam) {
-
-  /** Used for native method references. */
-  var arrayProto = Array.prototype;
-
-  /** Native method references. */
-  var splice = arrayProto.splice;
+define(['../internal/baseAt', '../internal/baseCompareAscending', '../internal/baseFlatten', '../internal/basePullAt', '../function/restParam'], function(baseAt, baseCompareAscending, baseFlatten, basePullAt, restParam) {
 
   /**
    * Removes elements from `array` corresponding to the given indexes and returns
@@ -35,17 +29,8 @@ define(['../internal/baseAt', '../internal/baseCompareAscending', '../internal/b
     array || (array = []);
     indexes = baseFlatten(indexes);
 
-    var length = indexes.length,
-        result = baseAt(array, indexes);
-
-    indexes.sort(baseCompareAscending);
-    while (length--) {
-      var index = parseFloat(indexes[length]);
-      if (index != previous && isIndex(index)) {
-        var previous = index;
-        splice.call(array, index, 1);
-      }
-    }
+    var result = baseAt(array, indexes);
+    basePullAt(array, indexes.sort(baseCompareAscending));
     return result;
   });
 

array/remove.js

@@ -1,10 +1,4 @@
-define(['../internal/baseCallback'], function(baseCallback) {
-
-  /** Used for native method references. */
-  var arrayProto = Array.prototype;
-
-  /** Native method references. */
-  var splice = arrayProto.splice;
+define(['../internal/baseCallback', '../internal/basePullAt'], function(baseCallback, basePullAt) {
 
   /**
    * Removes all elements from `array` that `predicate` returns truthy for
@@ -46,19 +40,23 @@ define(['../internal/baseCallback'], function(baseCallback) {
    * // => [2, 4]
    */
   function remove(array, predicate, thisArg) {
+    var result = [];
+    if (!(array && array.length)) {
+      return result;
+    }
     var index = -1,
-        length = array ? array.length : 0,
-        result = [];
+        indexes = [],
+        length = array.length;
 
     predicate = baseCallback(predicate, thisArg, 3);
     while (++index < length) {
       var value = array[index];
       if (predicate(value, index, array)) {
         result.push(value);
-        splice.call(array, index--, 1);
-        length--;
+        indexes.push(index);
       }
     }
+    basePullAt(array, indexes);
     return result;
   }
 

array/slice.js

@@ -3,7 +3,7 @@ define(['../internal/baseSlice', '../internal/isIterateeCall'], function(baseSli
   /**
    * Creates a slice of `array` from `start` up to, but not including, `end`.
    *
-   * **Note:** This function is used instead of `Array#slice` to support node
+   * **Note:** This method is used instead of `Array#slice` to support node
    * lists in IE < 9 and to ensure dense arrays are returned.
    *
    * @static

array/uniq.js

@@ -1,12 +1,13 @@
 define(['../internal/baseCallback', '../internal/baseUniq', '../internal/isIterateeCall', '../internal/sortedUniq'], function(baseCallback, baseUniq, isIterateeCall, sortedUniq) {
 
   /**
-   * Creates a duplicate-value-free version of an array using `SameValueZero`
-   * for equality comparisons. Providing `true` for `isSorted` performs a faster
-   * search algorithm for sorted arrays. If an iteratee function is provided it
-   * is invoked for each value in the array to generate the criterion by which
-   * uniqueness is computed. The `iteratee` is bound to `thisArg` and invoked
-   * with three arguments: (value, index, array).
+   * Creates a duplicate-free version of an array, using `SameValueZero` for
+   * equality comparisons, in which only the first occurence of each element
+   * is kept. Providing `true` for `isSorted` performs a faster search algorithm
+   * for sorted arrays. If an iteratee function is provided it is invoked for
+   * each element in the array to generate the criterion by which uniqueness
+   * is computed. The `iteratee` is bound to `thisArg` and invoked with three
+   * arguments: (value, index, array).
    *
    * If a property name is provided for `iteratee` the created `_.property`
    * style callback returns the property value of the given element.
@@ -34,8 +35,8 @@ define(['../internal/baseCallback', '../internal/baseUniq', '../internal/isItera
    * @returns {Array} Returns the new duplicate-value-free array.
    * @example
    *
-   * _.uniq([1, 2, 1]);
-   * // => [1, 2]
+   * _.uniq([2, 1, 2]);
+   * // => [2, 1]
    *
    * // using `isSorted`
    * _.uniq([1, 1, 2], true);

array/unzip.js

@@ -1,7 +1,4 @@
-define(['../internal/arrayMap', '../internal/arrayMax', '../internal/baseProperty'], function(arrayMap, arrayMax, baseProperty) {
-
-  /** Used to the length of n-tuples for `_.unzip`. */
-  var getLength = baseProperty('length');
+define(['../internal/arrayMap', '../internal/arrayMax', '../internal/baseProperty', '../internal/getLength'], function(arrayMap, arrayMax, baseProperty, getLength) {
 
   /**
    * This method is like `_.zip` except that it accepts an array of grouped

chain/lodash.js

@@ -45,8 +45,8 @@ define(['../internal/LazyWrapper', '../internal/LodashWrapper', '../internal/bas
    * `filter`, `flatten`, `flattenDeep`, `flow`, `flowRight`, `forEach`,
    * `forEachRight`, `forIn`, `forInRight`, `forOwn`, `forOwnRight`, `functions`,
    * `groupBy`, `indexBy`, `initial`, `intersection`, `invert`, `invoke`, `keys`,
-   * `keysIn`, `map`, `mapValues`, `matches`, `matchesProperty`, `memoize`, `merge`,
-   * `mixin`, `negate`, `noop`, `omit`, `once`, `pairs`, `partial`, `partialRight`,
+   * `keysIn`, `map`, `mapValues`, `matches`, `matchesProperty`, `memoize`,
+   * `merge`, `mixin`, `negate`, `omit`, `once`, `pairs`, `partial`, `partialRight`,
    * `partition`, `pick`, `plant`, `pluck`, `property`, `propertyOf`, `pull`,
    * `pullAt`, `push`, `range`, `rearg`, `reject`, `remove`, `rest`, `reverse`,
    * `shuffle`, `slice`, `sort`, `sortBy`, `sortByAll`, `sortByOrder`, `splice`,
@@ -60,15 +60,15 @@ define(['../internal/LazyWrapper', '../internal/LodashWrapper', '../internal/bas
    * `endsWith`, `escape`, `escapeRegExp`, `every`, `find`, `findIndex`, `findKey`,
    * `findLast`, `findLastIndex`, `findLastKey`, `findWhere`, `first`, `has`,
    * `identity`, `includes`, `indexOf`, `inRange`, `isArguments`, `isArray`,
-   * `isBoolean`, `isDate`, `isElement`, `isEmpty`, `isEqual`, `isError`,
-   * `isFinite`,`isFunction`, `isMatch`, `isNative`, `isNaN`, `isNull`, `isNumber`,
-   * `isObject`, `isPlainObject`, `isRegExp`, `isString`, `isUndefined`,
-   * `isTypedArray`, `join`, `kebabCase`, `last`, `lastIndexOf`, `max`, `min`,
-   * `noConflict`, `now`, `pad`, `padLeft`, `padRight`, `parseInt`, `pop`,
-   * `random`, `reduce`, `reduceRight`, `repeat`, `result`, `runInContext`,
-   * `shift`, `size`, `snakeCase`, `some`, `sortedIndex`, `sortedLastIndex`,
-   * `startCase`, `startsWith`, `sum`, `template`, `trim`, `trimLeft`,
-   * `trimRight`, `trunc`, `unescape`, `uniqueId`, `value`, and `words`
+   * `isBoolean`, `isDate`, `isElement`, `isEmpty`, `isEqual`, `isError`, `isFinite`
+   * `isFunction`, `isMatch`, `isNative`, `isNaN`, `isNull`, `isNumber`, `isObject`,
+   * `isPlainObject`, `isRegExp`, `isString`, `isUndefined`, `isTypedArray`,
+   * `join`, `kebabCase`, `last`, `lastIndexOf`, `max`, `min`, `noConflict`,
+   * `noop`, `now`, `pad`, `padLeft`, `padRight`, `parseInt`, `pop`, `random`,
+   * `reduce`, `reduceRight`, `repeat`, `result`, `runInContext`, `shift`, `size`,
+   * `snakeCase`, `some`, `sortedIndex`, `sortedLastIndex`, `startCase`, `startsWith`,
+   * `sum`, `template`, `trim`, `trimLeft`, `trimRight`, `trunc`, `unescape`,
+   * `uniqueId`, `value`, and `words`
    *
    * The wrapper method `sample` will return a wrapped value when `n` is provided,
    * otherwise an unwrapped value is returned.
@@ -83,8 +83,8 @@ define(['../internal/LazyWrapper', '../internal/LodashWrapper', '../internal/bas
    * var wrapped = _([1, 2, 3]);
    *
    * // returns an unwrapped value
-   * wrapped.reduce(function(sum, n) {
-   *   return sum + n;
+   * wrapped.reduce(function(total, n) {
+   *   return total + n;
    * });
    * // => 6
    *

collection/at.js

@@ -1,4 +1,4 @@
-define(['../internal/baseAt', '../internal/baseFlatten', '../internal/isLength', '../function/restParam', '../internal/toIterable'], function(baseAt, baseFlatten, isLength, restParam, toIterable) {
+define(['../internal/baseAt', '../internal/baseFlatten', '../internal/getLength', '../internal/isLength', '../function/restParam', '../internal/toIterable'], function(baseAt, baseFlatten, getLength, isLength, restParam, toIterable) {
 
   /**
    * Creates an array of elements corresponding to the given keys, or indexes,
@@ -21,7 +21,7 @@ define(['../internal/baseAt', '../internal/baseFlatten', '../internal/isLength',
    * // => ['barney', 'pebbles']
    */
   var at = restParam(function(collection, props) {
-    var length = collection ? collection.length : 0;
+    var length = collection ? getLength(collection) : 0;
     if (isLength(length)) {
       collection = toIterable(collection);
     }

collection/every.js

@@ -1,5 +1,8 @@
 define(['../internal/arrayEvery', '../internal/baseCallback', '../internal/baseEvery', '../lang/isArray', '../internal/isIterateeCall'], function(arrayEvery, baseCallback, baseEvery, isArray, isIterateeCall) {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /**
    * Checks if `predicate` returns truthy for **all** elements of `collection`.
    * The predicate is bound to `thisArg` and invoked with three arguments:
@@ -53,7 +56,7 @@ define(['../internal/arrayEvery', '../internal/baseCallback', '../internal/baseE
     if (thisArg && isIterateeCall(collection, predicate, thisArg)) {
       predicate = null;
     }
-    if (typeof predicate != 'function' || typeof thisArg != 'undefined') {
+    if (typeof predicate != 'function' || thisArg !== undefined) {
       predicate = baseCallback(predicate, thisArg, 3);
     }
     return func(collection, predicate);

collection/forEach.js

@@ -3,10 +3,10 @@ define(['../internal/arrayEach', '../internal/baseEach', '../internal/createForE
   /**
    * Iterates over elements of `collection` invoking `iteratee` for each element.
    * The `iteratee` is bound to `thisArg` and invoked with three arguments:
-   * (value, index|key, collection). Iterator functions may exit iteration early
+   * (value, index|key, collection). Iteratee functions may exit iteration early
    * by explicitly returning `false`.
    *
-   * **Note:** As with other "Collections" methods, objects with a `length` property
+   * **Note:** As with other "Collections" methods, objects with a "length" property
    * are iterated like arrays. To avoid this behavior `_.forIn` or `_.forOwn`
    * may be used for object iteration.
    *

collection/includes.js

@@ -1,4 +1,4 @@
-define(['../internal/baseIndexOf', '../lang/isArray', '../internal/isIterateeCall', '../internal/isLength', '../lang/isString', '../object/values'], function(baseIndexOf, isArray, isIterateeCall, isLength, isString, values) {
+define(['../internal/baseIndexOf', '../internal/getLength', '../lang/isArray', '../internal/isIterateeCall', '../internal/isLength', '../lang/isString', '../object/values'], function(baseIndexOf, getLength, isArray, isIterateeCall, isLength, isString, values) {
 
   /* Native method references for those with the same name as other `lodash` methods. */
   var nativeMax = Math.max;
@@ -36,7 +36,7 @@ define(['../internal/baseIndexOf', '../lang/isArray', '../internal/isIterateeCal
    * // => true
    */
   function includes(collection, target, fromIndex, guard) {
-    var length = collection ? collection.length : 0;
+    var length = collection ? getLength(collection) : 0;
     if (!isLength(length)) {
       collection = values(collection);
       length = collection.length;

collection/invoke.js

@@ -1,19 +1,16 @@
-define(['../internal/baseEach', '../internal/isLength', '../function/restParam'], function(baseEach, isLength, restParam) {
-
-  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
-  var undefined;
+define(['../internal/baseEach', '../internal/getLength', '../internal/invokePath', '../internal/isKey', '../internal/isLength', '../function/restParam'], function(baseEach, getLength, invokePath, isKey, isLength, restParam) {
 
   /**
-   * Invokes the method named by `methodName` on each element in `collection`,
-   * returning an array of the results of each invoked method. Any additional
-   * arguments are provided to each invoked method. If `methodName` is a function
-   * it is invoked for, and `this` bound to, each element in `collection`.
+   * Invokes the method at `path` on each element in `collection`, returning
+   * an array of the results of each invoked method. Any additional arguments
+   * are provided to each invoked method. If `methodName` is a function it is
+   * invoked for, and `this` bound to, each element in `collection`.
    *
    * @static
    * @memberOf _
    * @category Collection
    * @param {Array|Object|string} collection The collection to iterate over.
-   * @param {Function|string} methodName The name of the method to invoke or
+   * @param {Array|Function|string} path The path of the method to invoke or
    *  the function invoked per iteration.
    * @param {...*} [args] The arguments to invoke the method with.
    * @returns {Array} Returns the array of results.
@@ -25,15 +22,16 @@ define(['../internal/baseEach', '../internal/isLength', '../function/restParam']
    * _.invoke([123, 456], String.prototype.split, '');
    * // => [['1', '2', '3'], ['4', '5', '6']]
    */
-  var invoke = restParam(function(collection, methodName, args) {
+  var invoke = restParam(function(collection, path, args) {
     var index = -1,
-        isFunc = typeof methodName == 'function',
-        length = collection ? collection.length : 0,
+        isFunc = typeof path == 'function',
+        isProp = isKey(path),
+        length = getLength(collection),
         result = isLength(length) ? Array(length) : [];
 
     baseEach(collection, function(value) {
-      var func = isFunc ? methodName : (value != null && value[methodName]);
-      result[++index] = func ? func.apply(value, args) : undefined;
+      var func = isFunc ? path : (isProp && value != null && value[path]);
+      result[++index] = func ? func.apply(value, args) : invokePath(value, path, args);
     });
     return result;
   });

collection/map.js

@@ -32,7 +32,6 @@ define(['../internal/arrayMap', '../internal/baseCallback', '../internal/baseMap
    * @param {Array|Object|string} collection The collection to iterate over.
    * @param {Function|Object|string} [iteratee=_.identity] The function invoked
    *  per iteration.
-   *  create a `_.property` or `_.matches` style callback respectively.
    * @param {*} [thisArg] The `this` binding of `iteratee`.
    * @returns {Array} Returns the new mapped array.
    * @example

collection/pluck.js

@@ -1,13 +1,13 @@
-define(['../internal/baseProperty', './map'], function(baseProperty, map) {
+define(['./map', '../utility/property'], function(map, property) {
 
   /**
-   * Gets the value of `key` from all elements in `collection`.
+   * Gets the property value of `path` from all elements in `collection`.
    *
    * @static
    * @memberOf _
    * @category Collection
    * @param {Array|Object|string} collection The collection to iterate over.
-   * @param {string} key The key of the property to pluck.
+   * @param {Array|string} path The path of the property to pluck.
    * @returns {Array} Returns the property values.
    * @example
    *
@@ -23,8 +23,8 @@ define(['../internal/baseProperty', './map'], function(baseProperty, map) {
    * _.pluck(userIndex, 'age');
    * // => [36, 40] (iteration order is not guaranteed)
    */
-  function pluck(collection, key) {
-    return map(collection, baseProperty(key));
+  function pluck(collection, path) {
+    return map(collection, property(path));
   }
 
   return pluck;

collection/reduce.js

@@ -25,8 +25,8 @@ define(['../internal/arrayReduce', '../internal/baseEach', '../internal/createRe
    * @returns {*} Returns the accumulated value.
    * @example
    *
-   * _.reduce([1, 2], function(sum, n) {
-   *   return sum + n;
+   * _.reduce([1, 2], function(total, n) {
+   *   return total + n;
    * });
    * // => 3
    *

collection/size.js

@@ -1,4 +1,4 @@
-define(['../internal/isLength', '../object/keys'], function(isLength, keys) {
+define(['../internal/getLength', '../internal/isLength', '../object/keys'], function(getLength, isLength, keys) {
 
   /**
    * Gets the size of `collection` by returning its length for array-like
@@ -21,7 +21,7 @@ define(['../internal/isLength', '../object/keys'], function(isLength, keys) {
    * // => 7
    */
   function size(collection) {
-    var length = collection ? collection.length : 0;
+    var length = collection ? getLength(collection) : 0;
     return isLength(length) ? length : keys(collection).length;
   }
 

collection/some.js

@@ -1,5 +1,8 @@
 define(['../internal/arraySome', '../internal/baseCallback', '../internal/baseSome', '../lang/isArray', '../internal/isIterateeCall'], function(arraySome, baseCallback, baseSome, isArray, isIterateeCall) {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /**
    * Checks if `predicate` returns truthy for **any** element of `collection`.
    * The function returns as soon as it finds a passing value and does not iterate
@@ -54,7 +57,7 @@ define(['../internal/arraySome', '../internal/baseCallback', '../internal/baseSo
     if (thisArg && isIterateeCall(collection, predicate, thisArg)) {
       predicate = null;
     }
-    if (typeof predicate != 'function' || typeof thisArg != 'undefined') {
+    if (typeof predicate != 'function' || thisArg !== undefined) {
       predicate = baseCallback(predicate, thisArg, 3);
     }
     return func(collection, predicate);

collection/sortBy.js

@@ -1,4 +1,4 @@
-define(['../internal/baseCallback', '../internal/baseEach', '../internal/baseSortBy', '../internal/compareAscending', '../internal/isIterateeCall', '../internal/isLength'], function(baseCallback, baseEach, baseSortBy, compareAscending, isIterateeCall, isLength) {
+define(['../internal/baseCallback', '../internal/baseMap', '../internal/baseSortBy', '../internal/compareAscending', '../internal/isIterateeCall'], function(baseCallback, baseMap, baseSortBy, compareAscending, isIterateeCall) {
 
   /**
    * Creates an array of elements, sorted in ascending order by the results of
@@ -22,9 +22,8 @@ define(['../internal/baseCallback', '../internal/baseEach', '../internal/baseSor
    * @memberOf _
    * @category Collection
    * @param {Array|Object|string} collection The collection to iterate over.
-   * @param {Array|Function|Object|string} [iteratee=_.identity] The function
-   *  invoked per iteration. If a property name or an object is provided it is
-   *  used to create a `_.property` or `_.matches` style callback respectively.
+   * @param {Function|Object|string} [iteratee=_.identity] The function invoked
+   *  per iteration.
    * @param {*} [thisArg] The `this` binding of `iteratee`.
    * @returns {Array} Returns the new sorted array.
    * @example
@@ -53,16 +52,14 @@ define(['../internal/baseCallback', '../internal/baseEach', '../internal/baseSor
     if (collection == null) {
       return [];
     }
-    var index = -1,
-        length = collection.length,
-        result = isLength(length) ? Array(length) : [];
-
     if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
       iteratee = null;
     }
+    var index = -1;
     iteratee = baseCallback(iteratee, thisArg, 3);
-    baseEach(collection, function(value, key, collection) {
-      result[++index] = { 'criteria': iteratee(value, key, collection), 'index': index, 'value': value };
+
+    var result = baseMap(collection, function(value, key, collection) {
+      return { 'criteria': iteratee(value, key, collection), 'index': ++index, 'value': value };
     });
     return baseSortBy(result, compareAscending);
   }

collection/sortByAll.js

@@ -1,47 +1,50 @@
-define(['../internal/baseFlatten', '../internal/baseSortByOrder', '../internal/isIterateeCall'], function(baseFlatten, baseSortByOrder, isIterateeCall) {
+define(['../internal/baseFlatten', '../internal/baseSortByOrder', '../internal/isIterateeCall', '../function/restParam'], function(baseFlatten, baseSortByOrder, isIterateeCall, restParam) {
 
   /**
-   * This method is like `_.sortBy` except that it sorts by property names
-   * instead of an iteratee function.
+   * This method is like `_.sortBy` except that it can sort by multiple iteratees
+   * or property names.
+   *
+   * If a property name is provided for an iteratee the created `_.property`
+   * style callback returns the property value of the given element.
+   *
+   * If an object is provided for an iteratee the created `_.matches` style
+   * callback returns `true` for elements that have the properties of the given
+   * object, else `false`.
    *
    * @static
    * @memberOf _
    * @category Collection
    * @param {Array|Object|string} collection The collection to iterate over.
-   * @param {...(string|string[])} props The property names to sort by,
-   *  specified as individual property names or arrays of property names.
+   * @param {...(Function|Function[]|Object|Object[]|string|string[])} iteratees
+   *  The iteratees to sort by, specified as individual values or arrays of values.
    * @returns {Array} Returns the new sorted array.
    * @example
    *
    * var users = [
+   *   { 'user': 'fred',   'age': 48 },
    *   { 'user': 'barney', 'age': 36 },
-   *   { 'user': 'fred',   'age': 40 },
-   *   { 'user': 'barney', 'age': 26 },
-   *   { 'user': 'fred',   'age': 30 }
+   *   { 'user': 'fred',   'age': 42 },
+   *   { 'user': 'barney', 'age': 34 }
    * ];
    *
    * _.map(_.sortByAll(users, ['user', 'age']), _.values);
-   * // => [['barney', 26], ['barney', 36], ['fred', 30], ['fred', 40]]
+   * // => [['barney', 34], ['barney', 36], ['fred', 42], ['fred', 48]]
+   *
+   * _.map(_.sortByAll(users, 'user', function(chr) {
+   *   return Math.floor(chr.age / 10);
+   * }), _.values);
+   * // => [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 42]]
    */
-  function sortByAll() {
-    var args = arguments,
-        collection = args[0],
-        guard = args[3],
-        index = 0,
-        length = args.length - 1;
-
+  var sortByAll = restParam(function(collection, iteratees) {
     if (collection == null) {
       return [];
     }
-    var props = Array(length);
-    while (index < length) {
-      props[index] = args[++index];
+    var guard = iteratees[2];
+    if (guard && isIterateeCall(iteratees[0], iteratees[1], guard)) {
+      iteratees.length = 1;
     }
-    if (guard && isIterateeCall(args[1], args[2], guard)) {
-      props = args[1];
-    }
-    return baseSortByOrder(collection, baseFlatten(props), []);
-  }
+    return baseSortByOrder(collection, baseFlatten(iteratees), []);
+  });
 
   return sortByAll;
 });

collection/sortByOrder.js

@@ -2,45 +2,52 @@ define(['../internal/baseSortByOrder', '../lang/isArray', '../internal/isIterate
 
   /**
    * This method is like `_.sortByAll` except that it allows specifying the
-   * sort orders of the property names to sort by. A truthy value in `orders`
-   * will sort the corresponding property name in ascending order while a
-   * falsey value will sort it in descending order.
+   * sort orders of the iteratees to sort by. A truthy value in `orders` will
+   * sort the corresponding property name in ascending order while a falsey
+   * value will sort it in descending order.
+   *
+   * If a property name is provided for an iteratee the created `_.property`
+   * style callback returns the property value of the given element.
+   *
+   * If an object is provided for an iteratee the created `_.matches` style
+   * callback returns `true` for elements that have the properties of the given
+   * object, else `false`.
    *
    * @static
    * @memberOf _
    * @category Collection
    * @param {Array|Object|string} collection The collection to iterate over.
-   * @param {string[]} props The property names to sort by.
-   * @param {boolean[]} orders The sort orders of `props`.
+   * @param {Function[]|Object[]|string[]} iteratees The iteratees to sort by.
+   * @param {boolean[]} orders The sort orders of `iteratees`.
    * @param- {Object} [guard] Enables use as a callback for functions like `_.reduce`.
    * @returns {Array} Returns the new sorted array.
    * @example
    *
    * var users = [
-   *   { 'user': 'barney', 'age': 26 },
-   *   { 'user': 'fred',   'age': 40 },
-   *   { 'user': 'barney', 'age': 36 },
-   *   { 'user': 'fred',   'age': 30 }
+   *   { 'user': 'fred',   'age': 48 },
+   *   { 'user': 'barney', 'age': 34 },
+   *   { 'user': 'fred',   'age': 42 },
+   *   { 'user': 'barney', 'age': 36 }
    * ];
    *
    * // sort by `user` in ascending order and by `age` in descending order
    * _.map(_.sortByOrder(users, ['user', 'age'], [true, false]), _.values);
-   * // => [['barney', 36], ['barney', 26], ['fred', 40], ['fred', 30]]
+   * // => [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 42]]
    */
-  function sortByOrder(collection, props, orders, guard) {
+  function sortByOrder(collection, iteratees, orders, guard) {
     if (collection == null) {
       return [];
     }
-    if (guard && isIterateeCall(props, orders, guard)) {
+    if (guard && isIterateeCall(iteratees, orders, guard)) {
       orders = null;
     }
-    if (!isArray(props)) {
-      props = props == null ? [] : [props];
+    if (!isArray(iteratees)) {
+      iteratees = iteratees == null ? [] : [iteratees];
     }
     if (!isArray(orders)) {
       orders = orders == null ? [] : [orders];
     }
-    return baseSortByOrder(collection, props, orders);
+    return baseSortByOrder(collection, iteratees, orders);
   }
 
   return sortByOrder;

function/before.js

@@ -33,7 +33,8 @@ define([], function() {
     return function() {
       if (--n > 0) {
         result = func.apply(this, arguments);
-      } else {
+      }
+      if (n <= 1) {
         func = null;
       }
       return result;

function/bind.js

@@ -12,7 +12,7 @@ define(['../internal/createWrapper', '../internal/replaceHolders', './restParam'
    * The `_.bind.placeholder` value, which defaults to `_` in monolithic builds,
    * may be used as a placeholder for partially applied arguments.
    *
-   * **Note:** Unlike native `Function#bind` this method does not set the `length`
+   * **Note:** Unlike native `Function#bind` this method does not set the "length"
    * property of bound functions.
    *
    * @static

function/bindAll.js

@@ -9,7 +9,7 @@ define(['../internal/baseFlatten', '../internal/createWrapper', '../object/funct
    * of method names. If no method names are provided all enumerable function
    * properties, own and inherited, of `object` are bound.
    *
-   * **Note:** This method does not set the `length` property of bound functions.
+   * **Note:** This method does not set the "length" property of bound functions.
    *
    * @static
    * @memberOf _

function/bindKey.js

@@ -11,7 +11,7 @@ define(['../internal/createWrapper', '../internal/replaceHolders', './restParam'
    *
    * This method differs from `_.bind` by allowing bound functions to reference
    * methods that may be redefined or don't yet exist.
-   * See [Peter Michaux's article](http://michaux.ca/articles/lazy-function-definition-pattern)
+   * See [Peter Michaux's article](http://peter.michaux.ca/articles/lazy-function-definition-pattern)
    * for more details.
    *
    * The `_.bindKey.placeholder` value, which defaults to `_` in monolithic

function/curry.js

@@ -13,7 +13,7 @@ define(['../internal/createCurry'], function(createCurry) {
    * The `_.curry.placeholder` value, which defaults to `_` in monolithic builds,
    * may be used as a placeholder for provided arguments.
    *
-   * **Note:** This method does not set the `length` property of curried functions.
+   * **Note:** This method does not set the "length" property of curried functions.
    *
    * @static
    * @memberOf _

function/curryRight.js

@@ -10,7 +10,7 @@ define(['../internal/createCurry'], function(createCurry) {
    * The `_.curryRight.placeholder` value, which defaults to `_` in monolithic
    * builds, may be used as a placeholder for provided arguments.
    *
-   * **Note:** This method does not set the `length` property of curried functions.
+   * **Note:** This method does not set the "length" property of curried functions.
    *
    * @static
    * @memberOf _

function/once.js

@@ -18,7 +18,7 @@ define(['./before'], function(before) {
    * // `initialize` invokes `createApplication` once
    */
   function once(func) {
-    return before(func, 2);
+    return before(2, func);
   }
 
   return once;

function/partial.js

@@ -11,7 +11,7 @@ define(['../internal/createPartial'], function(createPartial) {
    * The `_.partial.placeholder` value, which defaults to `_` in monolithic
    * builds, may be used as a placeholder for partially applied arguments.
    *
-   * **Note:** This method does not set the `length` property of partially
+   * **Note:** This method does not set the "length" property of partially
    * applied functions.
    *
    * @static

function/partialRight.js

@@ -10,7 +10,7 @@ define(['../internal/createPartial'], function(createPartial) {
    * The `_.partialRight.placeholder` value, which defaults to `_` in monolithic
    * builds, may be used as a placeholder for partially applied arguments.
    *
-   * **Note:** This method does not set the `length` property of partially
+   * **Note:** This method does not set the "length" property of partially
    * applied functions.
    *
    * @static

function/restParam.js

@@ -1,5 +1,8 @@
 define([], function() {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /** Used as the `TypeError` message for "Functions" methods. */
   var FUNC_ERROR_TEXT = 'Expected a function';
 
@@ -32,7 +35,7 @@ define([], function() {
     if (typeof func != 'function') {
       throw new TypeError(FUNC_ERROR_TEXT);
     }
-    start = nativeMax(typeof start == 'undefined' ? (func.length - 1) : (+start || 0), 0);
+    start = nativeMax(start === undefined ? (func.length - 1) : (+start || 0), 0);
     return function() {
       var args = arguments,
           index = -1,

internal/assignDefaults.js

@@ -1,5 +1,8 @@
 define([], function() {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /**
    * Used by `_.defaults` to customize its `_.assign` use.
    *
@@ -9,7 +12,7 @@ define([], function() {
    * @returns {*} Returns the value to assign to the destination object.
    */
   function assignDefaults(objectValue, sourceValue) {
-    return typeof objectValue == 'undefined' ? sourceValue : objectValue;
+    return objectValue === undefined ? sourceValue : objectValue;
   }
 
   return assignDefaults;

internal/assignOwnDefaults.js

@@ -1,5 +1,8 @@
 define([], function() {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /** Used for native method references. */
   var objectProto = Object.prototype;
 
@@ -9,7 +12,7 @@ define([], function() {
   /**
    * Used by `_.template` to customize its `_.assign` use.
    *
-   * **Note:** This method is like `assignDefaults` except that it ignores
+   * **Note:** This function is like `assignDefaults` except that it ignores
    * inherited property values when checking if a property is `undefined`.
    *
    * @private
@@ -20,7 +23,7 @@ define([], function() {
    * @returns {*} Returns the value to assign to the destination object.
    */
   function assignOwnDefaults(objectValue, sourceValue, key, object) {
-    return (typeof objectValue == 'undefined' || !hasOwnProperty.call(object, key))
+    return (objectValue === undefined || !hasOwnProperty.call(object, key))
       ? sourceValue
       : objectValue;
   }

internal/assignWith.js

@@ -0,0 +1,44 @@
+define(['./getSymbols', '../object/keys'], function(getSymbols, keys) {
+
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
+  /** Used for native method references. */
+  var arrayProto = Array.prototype;
+
+  /** Native method references. */
+  var push = arrayProto.push;
+
+  /**
+   * A specialized version of `_.assign` for customizing assigned values without
+   * support for argument juggling, multiple sources, and `this` binding `customizer`
+   * functions.
+   *
+   * @private
+   * @param {Object} object The destination object.
+   * @param {Object} source The source object.
+   * @param {Function} customizer The function to customize assigned values.
+   * @returns {Object} Returns `object`.
+   */
+  function assignWith(object, source, customizer) {
+    var props = keys(source);
+    push.apply(props, getSymbols(source));
+
+    var index = -1,
+        length = props.length;
+
+    while (++index < length) {
+      var key = props[index],
+          value = object[key],
+          result = customizer(value, source[key], key, object, source);
+
+      if ((result === result ? (result !== value) : (value === value)) ||
+          (value === undefined && !(key in object))) {
+        object[key] = result;
+      }
+    }
+    return object;
+  }
+
+  return assignWith;
+});

internal/baseAssign.js

@@ -1,35 +1,38 @@
-define(['./baseCopy', '../object/keys'], function(baseCopy, keys) {
+define(['./baseCopy', './getSymbols', '../lang/isNative', '../object/keys'], function(baseCopy, getSymbols, isNative, keys) {
+
+  /** Native method references. */
+  var preventExtensions = isNative(Object.preventExtensions = Object.preventExtensions) && preventExtensions;
+
+  /** Used as `baseAssign`. */
+  var nativeAssign = (function() {
+    // Avoid `Object.assign` in Firefox 34-37 which have an early implementation
+    // with a now defunct try/catch behavior. See https://bugzilla.mozilla.org/show_bug.cgi?id=1103344
+    // for more details.
+    //
+    // Use `Object.preventExtensions` on a plain object instead of simply using
+    // `Object('x')` because Chrome and IE fail to throw an error when attempting
+    // to assign values to readonly indexes of strings in strict mode.
+    var object = { '1': 0 },
+        func = preventExtensions && isNative(func = Object.assign) && func;
+
+    try { func(preventExtensions(object), 'xo'); } catch(e) {}
+    return !object[1] && func;
+  }());
 
   /**
    * The base implementation of `_.assign` without support for argument juggling,
-   * multiple sources, and `this` binding `customizer` functions.
+   * multiple sources, and `customizer` functions.
    *
    * @private
    * @param {Object} object The destination object.
    * @param {Object} source The source object.
-   * @param {Function} [customizer] The function to customize assigning values.
-   * @returns {Object} Returns the destination object.
+   * @returns {Object} Returns `object`.
    */
-  function baseAssign(object, source, customizer) {
-    var props = keys(source);
-    if (!customizer) {
-      return baseCopy(source, object, props);
-    }
-    var index = -1,
-        length = props.length;
-
-    while (++index < length) {
-      var key = props[index],
-          value = object[key],
-          result = customizer(value, source[key], key, object, source);
-
-      if ((result === result ? (result !== value) : (value === value)) ||
-          (typeof value == 'undefined' && !(key in object))) {
-        object[key] = result;
-      }
-    }
-    return object;
-  }
+  var baseAssign = nativeAssign || function(object, source) {
+    return source == null
+      ? object
+      : baseCopy(source, getSymbols(source), baseCopy(source, keys(source), object));
+  };
 
   return baseAssign;
 });

internal/baseAt.js

@@ -4,12 +4,12 @@ define(['./isIndex', './isLength'], function(isIndex, isLength) {
   var undefined;
 
   /**
-   * The base implementation of `_.at` without support for strings and individual
-   * key arguments.
+   * The base implementation of `_.at` without support for string collections
+   * and individual key arguments.
    *
    * @private
    * @param {Array|Object} collection The collection to iterate over.
-   * @param {number[]|string[]} [props] The property names or indexes of elements to pick.
+   * @param {number[]|string[]} props The property names or indexes of elements to pick.
    * @returns {Array} Returns the new array of picked elements.
    */
   function baseAt(collection, props) {
@@ -22,7 +22,6 @@ define(['./isIndex', './isLength'], function(isIndex, isLength) {
     while(++index < propsLength) {
       var key = props[index];
       if (isArr) {
-        key = parseFloat(key);
         result[index] = isIndex(key, length) ? collection[key] : undefined;
       } else {
         result[index] = collection[key];

internal/baseCallback.js

@@ -1,4 +1,7 @@
-define(['./baseMatches', './baseMatchesProperty', './baseProperty', './bindCallback', '../utility/identity'], function(baseMatches, baseMatchesProperty, baseProperty, bindCallback, identity) {
+define(['./baseMatches', './baseMatchesProperty', './bindCallback', '../utility/identity', '../utility/property'], function(baseMatches, baseMatchesProperty, bindCallback, identity, property) {
+
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
 
   /**
    * The base implementation of `_.callback` which supports specifying the
@@ -13,7 +16,7 @@ define(['./baseMatches', './baseMatchesProperty', './baseProperty', './bindCallb
   function baseCallback(func, thisArg, argCount) {
     var type = typeof func;
     if (type == 'function') {
-      return typeof thisArg == 'undefined'
+      return thisArg === undefined
         ? func
         : bindCallback(func, thisArg, argCount);
     }
@@ -23,9 +26,9 @@ define(['./baseMatches', './baseMatchesProperty', './baseProperty', './bindCallb
     if (type == 'object') {
       return baseMatches(func);
     }
-    return typeof thisArg == 'undefined'
-      ? baseProperty(func + '')
-      : baseMatchesProperty(func + '', thisArg);
+    return thisArg === undefined
+      ? property(func)
+      : baseMatchesProperty(func, thisArg);
   }
 
   return baseCallback;

internal/baseClone.js

@@ -1,4 +1,7 @@
-define(['./arrayCopy', './arrayEach', './baseCopy', './baseForOwn', './initCloneArray', './initCloneByTag', './initCloneObject', '../lang/isArray', '../lang/isObject', '../object/keys'], function(arrayCopy, arrayEach, baseCopy, baseForOwn, initCloneArray, initCloneByTag, initCloneObject, isArray, isObject, keys) {
+define(['./arrayCopy', './arrayEach', './baseAssign', './baseForOwn', './initCloneArray', './initCloneByTag', './initCloneObject', '../lang/isArray', '../lang/isObject'], function(arrayCopy, arrayEach, baseAssign, baseForOwn, initCloneArray, initCloneByTag, initCloneObject, isArray, isObject) {
+
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
 
   /** `Object#toString` result references. */
   var argsTag = '[object Arguments]',
@@ -69,7 +72,7 @@ define(['./arrayCopy', './arrayEach', './baseCopy', './baseForOwn', './initClone
     if (customizer) {
       result = object ? customizer(value, key, object) : customizer(value);
     }
-    if (typeof result != 'undefined') {
+    if (result !== undefined) {
       return result;
     }
     if (!isObject(value)) {
@@ -88,7 +91,7 @@ define(['./arrayCopy', './arrayEach', './baseCopy', './baseForOwn', './initClone
       if (tag == objectTag || tag == argsTag || (isFunc && !object)) {
         result = initCloneObject(isFunc ? {} : value);
         if (!isDeep) {
-          return baseCopy(value, result, keys(value));
+          return baseAssign(result, value);
         }
       } else {
         return cloneableTags[tag]

internal/baseCompareAscending.js

@@ -1,5 +1,8 @@
 define([], function() {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /**
    * The base implementation of `compareAscending` which compares values and
    * sorts them in ascending order without guaranteeing a stable sort.
@@ -14,10 +17,10 @@ define([], function() {
       var valIsReflexive = value === value,
           othIsReflexive = other === other;
 
-      if (value > other || !valIsReflexive || (typeof value == 'undefined' && othIsReflexive)) {
+      if (value > other || !valIsReflexive || (value === undefined && othIsReflexive)) {
         return 1;
       }
-      if (value < other || !othIsReflexive || (typeof other == 'undefined' && valIsReflexive)) {
+      if (value < other || !othIsReflexive || (other === undefined && valIsReflexive)) {
         return -1;
       }
     }

internal/baseCopy.js

@@ -1,19 +1,17 @@
 define([], function() {
 
   /**
-   * Copies the properties of `source` to `object`.
+   * Copies properties of `source` to `object`.
    *
    * @private
    * @param {Object} source The object to copy properties from.
-   * @param {Object} [object={}] The object to copy properties to.
    * @param {Array} props The property names to copy.
+   * @param {Object} [object={}] The object to copy properties to.
    * @returns {Object} Returns `object`.
    */
-  function baseCopy(source, object, props) {
-    if (!props) {
-      props = object;
-      object = {};
-    }
+  function baseCopy(source, props, object) {
+    object || (object = {});
+
     var index = -1,
         length = props.length;
 

internal/baseFill.js

@@ -1,5 +1,8 @@
 define([], function() {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /**
    * The base implementation of `_.fill` without an iteratee call guard.
    *
@@ -17,7 +20,7 @@ define([], function() {
     if (start < 0) {
       start = -start > length ? 0 : (length + start);
     }
-    end = (typeof end == 'undefined' || end > length) ? length : (+end || 0);
+    end = (end === undefined || end > length) ? length : (+end || 0);
     if (end < 0) {
       end += length;
     }

internal/baseFor.js

@@ -3,7 +3,7 @@ define(['./createBaseFor'], function(createBaseFor) {
   /**
    * The base implementation of `baseForIn` and `baseForOwn` which iterates
    * over `object` properties returned by `keysFunc` invoking `iteratee` for
-   * each property. Iterator functions may exit iteration early by explicitly
+   * each property. Iteratee functions may exit iteration early by explicitly
    * returning `false`.
    *
    * @private

internal/baseGet.js

@@ -0,0 +1,33 @@
+define(['./toObject'], function(toObject) {
+
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
+  /**
+   * The base implementation of `get` without support for string paths
+   * and default values.
+   *
+   * @private
+   * @param {Object} object The object to query.
+   * @param {Array} path The path of the property to get.
+   * @param {string} [pathKey] The key representation of path.
+   * @returns {*} Returns the resolved value.
+   */
+  function baseGet(object, path, pathKey) {
+    if (object == null) {
+      return;
+    }
+    if (pathKey !== undefined && pathKey in toObject(object)) {
+      path = [pathKey];
+    }
+    var index = -1,
+        length = path.length;
+
+    while (object != null && ++index < length) {
+      var result = object = object[path[index]];
+    }
+    return result;
+  }
+
+  return baseGet;
+});

internal/baseIsEqualDeep.js

@@ -3,7 +3,6 @@ define(['./equalArrays', './equalByTag', './equalObjects', '../lang/isArray', '.
   /** `Object#toString` result references. */
   var argsTag = '[object Arguments]',
       arrayTag = '[object Array]',
-      funcTag = '[object Function]',
       objectTag = '[object Object]';
 
   /** Used for native method references. */
@@ -55,27 +54,23 @@ define(['./equalArrays', './equalByTag', './equalObjects', '../lang/isArray', '.
         othIsArr = isTypedArray(other);
       }
     }
-    var objIsObj = (objTag == objectTag || (isLoose && objTag == funcTag)),
-        othIsObj = (othTag == objectTag || (isLoose && othTag == funcTag)),
+    var objIsObj = objTag == objectTag,
+        othIsObj = othTag == objectTag,
         isSameTag = objTag == othTag;
 
     if (isSameTag && !(objIsArr || objIsObj)) {
       return equalByTag(object, other, objTag);
     }
-    if (isLoose) {
-      if (!isSameTag && !(objIsObj && othIsObj)) {
-        return false;
-      }
-    } else {
+    if (!isLoose) {
       var valWrapped = objIsObj && hasOwnProperty.call(object, '__wrapped__'),
           othWrapped = othIsObj && hasOwnProperty.call(other, '__wrapped__');
 
       if (valWrapped || othWrapped) {
         return equalFunc(valWrapped ? object.value() : object, othWrapped ? other.value() : other, customizer, isLoose, stackA, stackB);
       }
-      if (!isSameTag) {
-        return false;
-      }
+    }
+    if (!isSameTag) {
+      return false;
     }
     // Assume cyclic values are equal.
     // For more information on detecting circular references see https://es5.github.io/#JO.

internal/baseIsMatch.js

@@ -35,10 +35,10 @@ define(['./baseIsEqual'], function(baseIsEqual) {
           srcValue = values[index];
 
       if (noCustomizer && strictCompareFlags[index]) {
-        var result = typeof objValue != 'undefined' || (key in object);
+        var result = objValue !== undefined || (key in object);
       } else {
         result = customizer ? customizer(objValue, srcValue, key) : undefined;
-        if (typeof result == 'undefined') {
+        if (result === undefined) {
           result = baseIsEqual(srcValue, objValue, customizer, true);
         }
       }

internal/baseMap.js

@@ -1,4 +1,4 @@
-define(['./baseEach'], function(baseEach) {
+define(['./baseEach', './getLength', './isLength'], function(baseEach, getLength, isLength) {
 
   /**
    * The base implementation of `_.map` without support for callback shorthands
@@ -10,9 +10,12 @@ define(['./baseEach'], function(baseEach) {
    * @returns {Array} Returns the new mapped array.
    */
   function baseMap(collection, iteratee) {
-    var result = [];
+    var index = -1,
+        length = getLength(collection),
+        result = isLength(length) ? Array(length) : [];
+
     baseEach(collection, function(value, key, collection) {
-      result.push(iteratee(value, key, collection));
+      result[++index] = iteratee(value, key, collection);
     });
     return result;
   }

internal/baseMatches.js

@@ -1,5 +1,8 @@
 define(['./baseIsMatch', '../utility/constant', './isStrictComparable', '../object/keys', './toObject'], function(baseIsMatch, constant, isStrictComparable, keys, toObject) {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /**
    * The base implementation of `_.matches` which does not clone `source`.
    *
@@ -20,8 +23,10 @@ define(['./baseIsMatch', '../utility/constant', './isStrictComparable', '../obje
 
       if (isStrictComparable(value)) {
         return function(object) {
-          return object != null && object[key] === value &&
-            (typeof value != 'undefined' || (key in toObject(object)));
+          if (object == null) {
+            return false;
+          }
+          return object[key] === value && (value !== undefined || (key in toObject(object)));
         };
       }
     }

internal/baseMatchesProperty.js

@@ -1,23 +1,40 @@
-define(['./baseIsEqual', './isStrictComparable', './toObject'], function(baseIsEqual, isStrictComparable, toObject) {
+define(['./baseGet', './baseIsEqual', './baseSlice', '../lang/isArray', './isKey', './isStrictComparable', '../array/last', './toObject', './toPath'], function(baseGet, baseIsEqual, baseSlice, isArray, isKey, isStrictComparable, last, toObject, toPath) {
+
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
 
   /**
-   * The base implementation of `_.matchesProperty` which does not coerce `key`
-   * to a string.
+   * The base implementation of `_.matchesProperty` which does not which does
+   * not clone `value`.
    *
    * @private
-   * @param {string} key The key of the property to get.
+   * @param {string} path The path of the property to get.
    * @param {*} value The value to compare.
    * @returns {Function} Returns the new function.
    */
-  function baseMatchesProperty(key, value) {
-    if (isStrictComparable(value)) {
-      return function(object) {
-        return object != null && object[key] === value &&
-          (typeof value != 'undefined' || (key in toObject(object)));
-      };
-    }
+  function baseMatchesProperty(path, value) {
+    var isArr = isArray(path),
+        isCommon = isKey(path) && isStrictComparable(value),
+        pathKey = (path + '');
+
+    path = toPath(path);
     return function(object) {
-      return object != null && baseIsEqual(value, object[key], null, true);
+      if (object == null) {
+        return false;
+      }
+      var key = pathKey;
+      object = toObject(object);
+      if ((isArr || !isCommon) && !(key in object)) {
+        object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
+        if (object == null) {
+          return false;
+        }
+        key = last(path);
+        object = toObject(object);
+      }
+      return object[key] === value
+        ? (value !== undefined || (key in object))
+        : baseIsEqual(value, object[key], null, true);
     };
   }
 

internal/baseMerge.js

@@ -1,8 +1,14 @@
-define(['./arrayEach', './baseForOwn', './baseMergeDeep', '../lang/isArray', './isLength', '../lang/isObject', './isObjectLike', '../lang/isTypedArray'], function(arrayEach, baseForOwn, baseMergeDeep, isArray, isLength, isObject, isObjectLike, isTypedArray) {
+define(['./arrayEach', './baseMergeDeep', './getSymbols', '../lang/isArray', './isLength', '../lang/isObject', './isObjectLike', '../lang/isTypedArray', '../object/keys'], function(arrayEach, baseMergeDeep, getSymbols, isArray, isLength, isObject, isObjectLike, isTypedArray, keys) {
 
   /** Used as a safe reference for `undefined` in pre-ES5 environments. */
   var undefined;
 
+  /** Used for native method references. */
+  var arrayProto = Array.prototype;
+
+  /** Native method references. */
+  var push = arrayProto.push;
+
   /**
    * The base implementation of `_.merge` without support for argument juggling,
    * multiple sources, and `this` binding `customizer` functions.
@@ -13,29 +19,39 @@ define(['./arrayEach', './baseForOwn', './baseMergeDeep', '../lang/isArray', './
    * @param {Function} [customizer] The function to customize merging properties.
    * @param {Array} [stackA=[]] Tracks traversed source objects.
    * @param {Array} [stackB=[]] Associates values with source counterparts.
-   * @returns {Object} Returns the destination object.
+   * @returns {Object} Returns `object`.
    */
   function baseMerge(object, source, customizer, stackA, stackB) {
     if (!isObject(object)) {
       return object;
     }
     var isSrcArr = isLength(source.length) && (isArray(source) || isTypedArray(source));
-    (isSrcArr ? arrayEach : baseForOwn)(source, function(srcValue, key, source) {
+    if (!isSrcArr) {
+      var props = keys(source);
+      push.apply(props, getSymbols(source));
+    }
+    arrayEach(props || source, function(srcValue, key) {
+      if (props) {
+        key = srcValue;
+        srcValue = source[key];
+      }
       if (isObjectLike(srcValue)) {
         stackA || (stackA = []);
         stackB || (stackB = []);
-        return baseMergeDeep(object, source, key, baseMerge, customizer, stackA, stackB);
+        baseMergeDeep(object, source, key, baseMerge, customizer, stackA, stackB);
       }
-      var value = object[key],
-          result = customizer ? customizer(value, srcValue, key, object, source) : undefined,
-          isCommon = typeof result == 'undefined';
+      else {
+        var value = object[key],
+            result = customizer ? customizer(value, srcValue, key, object, source) : undefined,
+            isCommon = result === undefined;
 
-      if (isCommon) {
-        result = srcValue;
-      }
-      if ((isSrcArr || typeof result != 'undefined') &&
-          (isCommon || (result === result ? (result !== value) : (value === value)))) {
-        object[key] = result;
+        if (isCommon) {
+          result = srcValue;
+        }
+        if ((isSrcArr || result !== undefined) &&
+            (isCommon || (result === result ? (result !== value) : (value === value)))) {
+          object[key] = result;
+        }
       }
     });
     return object;

internal/baseMergeDeep.js

@@ -1,4 +1,4 @@
-define(['./arrayCopy', '../lang/isArguments', '../lang/isArray', './isLength', '../lang/isPlainObject', '../lang/isTypedArray', '../lang/toPlainObject'], function(arrayCopy, isArguments, isArray, isLength, isPlainObject, isTypedArray, toPlainObject) {
+define(['./arrayCopy', './getLength', '../lang/isArguments', '../lang/isArray', './isLength', '../lang/isPlainObject', '../lang/isTypedArray', '../lang/toPlainObject'], function(arrayCopy, getLength, isArguments, isArray, isLength, isPlainObject, isTypedArray, toPlainObject) {
 
   /** Used as a safe reference for `undefined` in pre-ES5 environments. */
   var undefined;
@@ -30,14 +30,14 @@ define(['./arrayCopy', '../lang/isArguments', '../lang/isArray', './isLength', '
     }
     var value = object[key],
         result = customizer ? customizer(value, srcValue, key, object, source) : undefined,
-        isCommon = typeof result == 'undefined';
+        isCommon = result === undefined;
 
     if (isCommon) {
       result = srcValue;
       if (isLength(srcValue.length) && (isArray(srcValue) || isTypedArray(srcValue))) {
         result = isArray(value)
           ? value
-          : ((value && value.length) ? arrayCopy(value) : []);
+          : (getLength(value) ? arrayCopy(value) : []);
       }
       else if (isPlainObject(srcValue) || isArguments(srcValue)) {
         result = isArguments(value)

internal/baseProperty.js

@@ -4,7 +4,7 @@ define([], function() {
   var undefined;
 
   /**
-   * The base implementation of `_.property` which does not coerce `key` to a string.
+   * The base implementation of `_.property` without support for deep paths.
    *
    * @private
    * @param {string} key The key of the property to get.

internal/basePropertyDeep.js

@@ -0,0 +1,19 @@
+define(['./baseGet', './toPath'], function(baseGet, toPath) {
+
+  /**
+   * A specialized version of `baseProperty` which supports deep paths.
+   *
+   * @private
+   * @param {Array|string} path The path of the property to get.
+   * @returns {Function} Returns the new function.
+   */
+  function basePropertyDeep(path) {
+    var pathKey = (path + '');
+    path = toPath(path);
+    return function(object) {
+      return baseGet(object, path, pathKey);
+    };
+  }
+
+  return basePropertyDeep;
+});

internal/basePullAt.js

@@ -0,0 +1,31 @@
+define(['./isIndex'], function(isIndex) {
+
+  /** Used for native method references. */
+  var arrayProto = Array.prototype;
+
+  /** Native method references. */
+  var splice = arrayProto.splice;
+
+  /**
+   * The base implementation of `_.pullAt` without support for individual
+   * index arguments and capturing the removed elements.
+   *
+   * @private
+   * @param {Array} array The array to modify.
+   * @param {number[]} indexes The indexes of elements to remove.
+   * @returns {Array} Returns `array`.
+   */
+  function basePullAt(array, indexes) {
+    var length = indexes.length;
+    while (length--) {
+      var index = parseFloat(indexes[length]);
+      if (index != previous && isIndex(index)) {
+        var previous = index;
+        splice.call(array, index, 1);
+      }
+    }
+    return array;
+  }
+
+  return basePullAt;
+});

internal/baseSlice.js

@@ -1,5 +1,8 @@
 define([], function() {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /**
    * The base implementation of `_.slice` without an iteratee call guard.
    *
@@ -17,7 +20,7 @@ define([], function() {
     if (start < 0) {
       start = -start > length ? 0 : (length + start);
     }
-    end = (typeof end == 'undefined' || end > length) ? length : (+end || 0);
+    end = (end === undefined || end > length) ? length : (+end || 0);
     if (end < 0) {
       end += length;
     }

internal/baseSortByOrder.js

@@ -1,30 +1,22 @@
-define(['./baseEach', './baseSortBy', './compareMultiple', './isLength'], function(baseEach, baseSortBy, compareMultiple, isLength) {
-
-  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
-  var undefined;
+define(['./arrayMap', './baseCallback', './baseMap', './baseSortBy', './compareMultiple'], function(arrayMap, baseCallback, baseMap, baseSortBy, compareMultiple) {
 
   /**
    * The base implementation of `_.sortByOrder` without param guards.
    *
    * @private
    * @param {Array|Object|string} collection The collection to iterate over.
-   * @param {string[]} props The property names to sort by.
-   * @param {boolean[]} orders The sort orders of `props`.
+   * @param {Function[]|Object[]|string[]} iteratees The iteratees to sort by.
+   * @param {boolean[]} orders The sort orders of `iteratees`.
    * @returns {Array} Returns the new sorted array.
    */
-  function baseSortByOrder(collection, props, orders) {
-    var index = -1,
-        length = collection.length,
-        result = isLength(length) ? Array(length) : [];
+  function baseSortByOrder(collection, iteratees, orders) {
+    var index = -1;
 
-    baseEach(collection, function(value) {
-      var length = props.length,
-          criteria = Array(length);
+    iteratees = arrayMap(iteratees, function(iteratee) { return baseCallback(iteratee); });
 
-      while (length--) {
-        criteria[length] = value == null ? undefined : value[props[length]];
-      }
-      result[++index] = { 'criteria': criteria, 'index': index, 'value': value };
+    var result = baseMap(collection, function(value) {
+      var criteria = arrayMap(iteratees, function(iteratee) { return iteratee(value); });
+      return { 'criteria': criteria, 'index': ++index, 'value': value };
     });
 
     return baseSortBy(result, function(object, other) {

internal/baseValues.js

@@ -3,7 +3,7 @@ define([], function() {
   /**
    * The base implementation of `_.values` and `_.valuesIn` which creates an
    * array of `object` property values corresponding to the property names
-   * returned by `keysFunc`.
+   * of `props`.
    *
    * @private
    * @param {Object} object The object to query.

internal/binaryIndexBy.js

@@ -1,5 +1,8 @@
 define([], function() {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /** Native method references. */
   var floor = Math.floor;
 
@@ -29,7 +32,7 @@ define([], function() {
     var low = 0,
         high = array ? array.length : 0,
         valIsNaN = value !== value,
-        valIsUndef = typeof value == 'undefined';
+        valIsUndef = value === undefined;
 
     while (low < high) {
       var mid = floor((low + high) / 2),
@@ -39,7 +42,7 @@ define([], function() {
       if (valIsNaN) {
         var setLow = isReflexive || retHighest;
       } else if (valIsUndef) {
-        setLow = isReflexive && (retHighest || typeof computed != 'undefined');
+        setLow = isReflexive && (retHighest || computed !== undefined);
       } else {
         setLow = retHighest ? (computed <= value) : (computed < value);
       }

internal/bindCallback.js

@@ -1,5 +1,8 @@
 define(['../utility/identity'], function(identity) {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /**
    * A specialized version of `baseCallback` which only supports `this` binding
    * and specifying the number of arguments to provide to `func`.
@@ -14,7 +17,7 @@ define(['../utility/identity'], function(identity) {
     if (typeof func != 'function') {
       return identity;
     }
-    if (typeof thisArg == 'undefined') {
+    if (thisArg === undefined) {
       return func;
     }
     switch (argCount) {

internal/compareMultiple.js

@@ -4,7 +4,7 @@ define(['./baseCompareAscending'], function(baseCompareAscending) {
    * Used by `_.sortByOrder` to compare multiple properties of each element
    * in a collection and stable sort them in the following order:
    *
-   * If orders is unspecified, sort in ascending order for all properties.
+   * If `orders` is unspecified, sort in ascending order for all properties.
    * Otherwise, for each property, sort in ascending order if its corresponding value in
    * orders is true, and descending order if false.
    *

internal/createAssigner.js

@@ -1,4 +1,4 @@
-define(['./bindCallback', './isIterateeCall'], function(bindCallback, isIterateeCall) {
+define(['./bindCallback', './isIterateeCall', '../function/restParam'], function(bindCallback, isIterateeCall, restParam) {
 
   /**
    * Creates a function that assigns properties of source object(s) to a given
@@ -11,38 +11,32 @@ define(['./bindCallback', './isIterateeCall'], function(bindCallback, isIteratee
    * @returns {Function} Returns the new assigner function.
    */
   function createAssigner(assigner) {
-    return function() {
-      var args = arguments,
-          length = args.length,
-          object = args[0];
+    return restParam(function(object, sources) {
+      var index = -1,
+          length = object == null ? 0 : sources.length,
+          customizer = length > 2 && sources[length - 2],
+          guard = length > 2 && sources[2],
+          thisArg = length > 1 && sources[length - 1];
 
-      if (length < 2 || object == null) {
-        return object;
-      }
-      var customizer = args[length - 2],
-          thisArg = args[length - 1],
-          guard = args[3];
-
-      if (length > 3 && typeof customizer == 'function') {
+      if (typeof customizer == 'function') {
         customizer = bindCallback(customizer, thisArg, 5);
         length -= 2;
       } else {
-        customizer = (length > 2 && typeof thisArg == 'function') ? thisArg : null;
+        customizer = typeof thisArg == 'function' ? thisArg : null;
         length -= (customizer ? 1 : 0);
       }
-      if (guard && isIterateeCall(args[1], args[2], guard)) {
-        customizer = length == 3 ? null : customizer;
-        length = 2;
+      if (guard && isIterateeCall(sources[0], sources[1], guard)) {
+        customizer = length < 3 ? null : customizer;
+        length = 1;
       }
-      var index = 0;
       while (++index < length) {
-        var source = args[index];
+        var source = sources[index];
         if (source) {
           assigner(object, source, customizer);
         }
       }
       return object;
-    };
+    });
   }
 
   return createAssigner;

internal/createBaseEach.js

@@ -1,4 +1,4 @@
-define(['./isLength', './toObject'], function(isLength, toObject) {
+define(['./getLength', './isLength', './toObject'], function(getLength, isLength, toObject) {
 
   /**
    * Creates a `baseEach` or `baseEachRight` function.
@@ -10,7 +10,7 @@ define(['./isLength', './toObject'], function(isLength, toObject) {
    */
   function createBaseEach(eachFunc, fromRight) {
     return function(collection, iteratee) {
-      var length = collection ? collection.length : 0;
+      var length = collection ? getLength(collection) : 0;
       if (!isLength(length)) {
         return eachFunc(collection, iteratee);
       }

internal/createForEach.js

@@ -1,5 +1,8 @@
 define(['./bindCallback', '../lang/isArray'], function(bindCallback, isArray) {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /**
    * Creates a function for `_.forEach` or `_.forEachRight`.
    *
@@ -10,7 +13,7 @@ define(['./bindCallback', '../lang/isArray'], function(bindCallback, isArray) {
    */
   function createForEach(arrayFunc, eachFunc) {
     return function(collection, iteratee, thisArg) {
-      return (typeof iteratee == 'function' && typeof thisArg == 'undefined' && isArray(collection))
+      return (typeof iteratee == 'function' && thisArg === undefined && isArray(collection))
         ? arrayFunc(collection, iteratee)
         : eachFunc(collection, bindCallback(iteratee, thisArg, 3));
     };

internal/createForIn.js

@@ -1,5 +1,8 @@
 define(['./bindCallback', '../object/keysIn'], function(bindCallback, keysIn) {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /**
    * Creates a function for `_.forIn` or `_.forInRight`.
    *
@@ -9,7 +12,7 @@ define(['./bindCallback', '../object/keysIn'], function(bindCallback, keysIn) {
    */
   function createForIn(objectFunc) {
     return function(object, iteratee, thisArg) {
-      if (typeof iteratee != 'function' || typeof thisArg != 'undefined') {
+      if (typeof iteratee != 'function' || thisArg !== undefined) {
         iteratee = bindCallback(iteratee, thisArg, 3);
       }
       return objectFunc(object, iteratee, keysIn);

internal/createForOwn.js

@@ -1,5 +1,8 @@
 define(['./bindCallback'], function(bindCallback) {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /**
    * Creates a function for `_.forOwn` or `_.forOwnRight`.
    *
@@ -9,7 +12,7 @@ define(['./bindCallback'], function(bindCallback) {
    */
   function createForOwn(objectFunc) {
     return function(object, iteratee, thisArg) {
-      if (typeof iteratee != 'function' || typeof thisArg != 'undefined') {
+      if (typeof iteratee != 'function' || thisArg !== undefined) {
         iteratee = bindCallback(iteratee, thisArg, 3);
       }
       return objectFunc(object, iteratee);

internal/createReduce.js

@@ -1,5 +1,8 @@
 define(['./baseCallback', './baseReduce', '../lang/isArray'], function(baseCallback, baseReduce, isArray) {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /**
    * Creates a function for `_.reduce` or `_.reduceRight`.
    *
@@ -11,7 +14,7 @@ define(['./baseCallback', './baseReduce', '../lang/isArray'], function(baseCallb
   function createReduce(arrayFunc, eachFunc) {
     return function(collection, iteratee, accumulator, thisArg) {
       var initFromArray = arguments.length < 3;
-      return (typeof iteratee == 'function' && typeof thisArg == 'undefined' && isArray(collection))
+      return (typeof iteratee == 'function' && thisArg === undefined && isArray(collection))
         ? arrayFunc(collection, iteratee, accumulator, initFromArray)
         : baseReduce(collection, baseCallback(iteratee, thisArg, 4), accumulator, initFromArray, eachFunc);
     };

internal/equalArrays.js

@@ -37,7 +37,7 @@ define([], function() {
           ? customizer(othValue, arrValue, index)
           : customizer(arrValue, othValue, index);
       }
-      if (typeof result == 'undefined') {
+      if (result === undefined) {
         // Recursively compare arrays (susceptible to call stack limits).
         if (isLoose) {
           var othIndex = othLength;

internal/equalObjects.js

@@ -49,7 +49,7 @@ define(['../object/keys'], function(keys) {
             ? customizer(othValue, objValue, key)
             : customizer(objValue, othValue, key);
         }
-        if (typeof result == 'undefined') {
+        if (result === undefined) {
           // Recursively compare objects (susceptible to call stack limits).
           result = (objValue && objValue === othValue) || equalFunc(objValue, othValue, customizer, isLoose, stackA, stackB);
         }

internal/getLength.js

@@ -0,0 +1,16 @@
+define(['./baseProperty'], function(baseProperty) {
+
+  /**
+   * Gets the "length" property value of `object`.
+   *
+   * **Note:** This function is used to avoid a [JIT bug](https://bugs.webkit.org/show_bug.cgi?id=142792)
+   * in Safari on iOS 8.1 ARM64.
+   *
+   * @private
+   * @param {Object} object The object to query.
+   * @returns {*} Returns the "length" value.
+   */
+  var getLength = baseProperty('length');
+
+  return getLength;
+});

internal/getSymbols.js

@@ -0,0 +1,18 @@
+define(['../utility/constant', '../lang/isNative', './toObject'], function(constant, isNative, toObject) {
+
+  /** Native method references. */
+  var getOwnPropertySymbols = isNative(getOwnPropertySymbols = Object.getOwnPropertySymbols) && getOwnPropertySymbols;
+
+  /**
+   * Creates an array of the own symbols of `object`.
+   *
+   * @private
+   * @param {Object} object The object to query.
+   * @returns {Array} Returns the array of symbols.
+   */
+  var getSymbols = !getOwnPropertySymbols ? constant([]) : function(object) {
+    return getOwnPropertySymbols(toObject(object));
+  };
+
+  return getSymbols;
+});

internal/initCloneByTag.js

@@ -27,7 +27,6 @@ define(['./bufferClone'], function(bufferClone) {
    * **Note:** This function only supports cloning values with tags of
    * `Boolean`, `Date`, `Error`, `Number`, `RegExp`, or `String`.
    *
-   *
    * @private
    * @param {Object} object The object to clone.
    * @param {string} tag The `toStringTag` of the object to clone.

internal/invokePath.js

@@ -0,0 +1,26 @@
+define(['./baseGet', './baseSlice', './isKey', '../array/last', './toPath'], function(baseGet, baseSlice, isKey, last, toPath) {
+
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
+  /**
+   * Invokes the method at `path` on `object`.
+   *
+   * @private
+   * @param {Object} object The object to query.
+   * @param {Array|string} path The path of the method to invoke.
+   * @param {Array} args The arguments to invoke the method with.
+   * @returns {*} Returns the result of the invoked method.
+   */
+  function invokePath(object, path, args) {
+    if (object != null && !isKey(path, object)) {
+      path = toPath(path);
+      object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
+      path = last(path);
+    }
+    var func = object == null ? object : object[path];
+    return func == null ? undefined : func.apply(object, args);
+  }
+
+  return invokePath;
+});

internal/isIterateeCall.js

@@ -1,4 +1,4 @@
-define(['./isIndex', './isLength', '../lang/isObject'], function(isIndex, isLength, isObject) {
+define(['./getLength', './isIndex', './isLength', '../lang/isObject'], function(getLength, isIndex, isLength, isObject) {
 
   /**
    * Checks if the provided arguments are from an iteratee call.
@@ -15,7 +15,7 @@ define(['./isIndex', './isLength', '../lang/isObject'], function(isIndex, isLeng
     }
     var type = typeof index;
     if (type == 'number') {
-      var length = object.length,
+      var length = getLength(object),
           prereq = isLength(length) && isIndex(index, length);
     } else {
       prereq = type == 'string' && index in object;

internal/isKey.js

@@ -0,0 +1,28 @@
+define(['../lang/isArray', './toObject'], function(isArray, toObject) {
+
+  /** Used to match property names within property paths. */
+  var reIsDeepProp = /\.|\[(?:[^[\]]+|(["'])(?:(?!\1)[^\n\\]|\\.)*?)\1\]/,
+      reIsPlainProp = /^\w*$/;
+
+  /**
+   * Checks if `value` is a property name and not a property path.
+   *
+   * @private
+   * @param {*} value The value to check.
+   * @param {Object} [object] The object to query keys on.
+   * @returns {boolean} Returns `true` if `value` is a property name, else `false`.
+   */
+  function isKey(value, object) {
+    var type = typeof value;
+    if ((type == 'string' && reIsPlainProp.test(value)) || type == 'number') {
+      return true;
+    }
+    if (isArray(value)) {
+      return false;
+    }
+    var result = !reIsDeepProp.test(value);
+    return result || (object != null && value in toObject(object));
+  }
+
+  return isKey;
+});

internal/mapSet.js

@@ -1,7 +1,7 @@
 define([], function() {
 
   /**
-   * Adds `value` to `key` of the cache.
+   * Sets `value` to `key` of the cache.
    *
    * @private
    * @name set

internal/pickByArray.js

@@ -2,7 +2,7 @@ define(['./toObject'], function(toObject) {
 
   /**
    * A specialized version of `_.pick` that picks `object` properties specified
-   * by the `props` array.
+   * by `props`.
    *
    * @private
    * @param {Object} object The source object.

internal/root.js

@@ -13,7 +13,7 @@ define([], function() {
   var freeModule = objectTypes[typeof module] && module && !module.nodeType && module;
 
   /** Detect free variable `global` from Node.js. */
-  var freeGlobal = freeExports && freeModule && typeof global == 'object' && global;
+  var freeGlobal = freeExports && freeModule && typeof global == 'object' && global && global.Object && global;
 
   /** Detect free variable `self`. */
   var freeSelf = objectTypes[typeof self] && self && self.Object && self;

internal/shimIsPlainObject.js

@@ -1,5 +1,8 @@
 define(['./baseForIn', './isObjectLike'], function(baseForIn, isObjectLike) {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /** `Object#toString` result references. */
   var objectTag = '[object Object]';
 
@@ -43,7 +46,7 @@ define(['./baseForIn', './isObjectLike'], function(baseForIn, isObjectLike) {
     baseForIn(value, function(subValue, key) {
       result = key;
     });
-    return typeof result == 'undefined' || hasOwnProperty.call(value, result);
+    return result === undefined || hasOwnProperty.call(value, result);
   }
 
   return shimIsPlainObject;

internal/shimKeys.js

@@ -11,7 +11,7 @@ define(['../lang/isArguments', '../lang/isArray', './isIndex', './isLength', '..
    * own enumerable property names of `object`.
    *
    * @private
-   * @param {Object} object The object to inspect.
+   * @param {Object} object The object to query.
    * @returns {Array} Returns the array of property names.
    */
   function shimKeys(object) {

internal/toIterable.js

@@ -1,4 +1,4 @@
-define(['./isLength', '../lang/isObject', '../object/values'], function(isLength, isObject, values) {
+define(['./getLength', './isLength', '../lang/isObject', '../object/values'], function(getLength, isLength, isObject, values) {
 
   /**
    * Converts `value` to an array-like object if it is not one.
@@ -11,7 +11,7 @@ define(['./isLength', '../lang/isObject', '../object/values'], function(isLength
     if (value == null) {
       return [];
     }
-    if (!isLength(value.length)) {
+    if (!isLength(getLength(value))) {
       return values(value);
     }
     return isObject(value) ? value : Object(value);

internal/toPath.js

@@ -0,0 +1,28 @@
+define(['./baseToString', '../lang/isArray'], function(baseToString, isArray) {
+
+  /** Used to match property names within property paths. */
+  var rePropName = /[^.[\]]+|\[(?:(-?\d+(?:\.\d+)?)|(["'])((?:(?!\2)[^\n\\]|\\.)*?)\2)\]/g;
+
+  /** Used to match backslashes in property paths. */
+  var reEscapeChar = /\\(\\)?/g;
+
+  /**
+   * Converts `value` to property path array if it is not one.
+   *
+   * @private
+   * @param {*} value The value to process.
+   * @returns {Array} Returns the property path array.
+   */
+  function toPath(value) {
+    if (isArray(value)) {
+      return value;
+    }
+    var result = [];
+    baseToString(value).replace(rePropName, function(match, number, quote, string) {
+      result.push(quote ? string.replace(reEscapeChar, '$1') : (number || match));
+    });
+    return result;
+  }
+
+  return toPath;
+});

lang/isEmpty.js

@@ -1,4 +1,4 @@
-define(['./isArguments', './isArray', './isFunction', '../internal/isLength', '../internal/isObjectLike', './isString', '../object/keys'], function(isArguments, isArray, isFunction, isLength, isObjectLike, isString, keys) {
+define(['../internal/getLength', './isArguments', './isArray', './isFunction', '../internal/isLength', '../internal/isObjectLike', './isString', '../object/keys'], function(getLength, isArguments, isArray, isFunction, isLength, isObjectLike, isString, keys) {
 
   /**
    * Checks if `value` is empty. A value is considered empty unless it is an
@@ -31,7 +31,7 @@ define(['./isArguments', './isArray', './isFunction', '../internal/isLength', '.
     if (value == null) {
       return true;
     }
-    var length = value.length;
+    var length = getLength(value);
     if (isLength(length) && (isArray(value) || isString(value) || isArguments(value) ||
         (isObjectLike(value) && isFunction(value.splice)))) {
       return !length;

lang/isEqual.js

@@ -21,7 +21,7 @@ define(['../internal/baseIsEqual', '../internal/bindCallback', '../internal/isSt
    * @category Lang
    * @param {*} value The value to compare.
    * @param {*} other The other value to compare.
-   * @param {Function} [customizer] The function to customize comparing values.
+   * @param {Function} [customizer] The function to customize value comparisons.
    * @param {*} [thisArg] The `this` binding of `customizer`.
    * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
    * @example
@@ -52,7 +52,7 @@ define(['../internal/baseIsEqual', '../internal/bindCallback', '../internal/isSt
       return value === other;
     }
     var result = customizer ? customizer(value, other) : undefined;
-    return typeof result == 'undefined' ? baseIsEqual(value, other, customizer) : !!result;
+    return result === undefined ? baseIsEqual(value, other, customizer) : !!result;
   }
 
   return isEqual;

lang/isMatch.js

@@ -1,5 +1,8 @@
 define(['../internal/baseIsMatch', '../internal/bindCallback', '../internal/isStrictComparable', '../object/keys', '../internal/toObject'], function(baseIsMatch, bindCallback, isStrictComparable, keys, toObject) {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /**
    * Performs a deep comparison between `object` and `source` to determine if
    * `object` contains equivalent property values. If `customizer` is provided
@@ -17,7 +20,7 @@ define(['../internal/baseIsMatch', '../internal/bindCallback', '../internal/isSt
    * @category Lang
    * @param {Object} object The object to inspect.
    * @param {Object} source The object of property values to match.
-   * @param {Function} [customizer] The function to customize comparing values.
+   * @param {Function} [customizer] The function to customize value comparisons.
    * @param {*} [thisArg] The `this` binding of `customizer`.
    * @returns {boolean} Returns `true` if `object` is a match, else `false`.
    * @example
@@ -50,12 +53,13 @@ define(['../internal/baseIsMatch', '../internal/bindCallback', '../internal/isSt
       return false;
     }
     customizer = typeof customizer == 'function' && bindCallback(customizer, thisArg, 3);
+    object = toObject(object);
     if (!customizer && length == 1) {
       var key = props[0],
           value = source[key];
 
       if (isStrictComparable(value)) {
-        return value === object[key] && (typeof value != 'undefined' || (key in toObject(object)));
+        return value === object[key] && (value !== undefined || (key in object));
       }
     }
     var values = Array(length),
@@ -65,7 +69,7 @@ define(['../internal/baseIsMatch', '../internal/bindCallback', '../internal/isSt
       value = values[length] = source[props[length]];
       strictCompareFlags[length] = isStrictComparable(value);
     }
-    return baseIsMatch(toObject(object), props, values, strictCompareFlags, customizer);
+    return baseIsMatch(object, props, values, strictCompareFlags, customizer);
   }
 
   return isMatch;

lang/isNative.js

@@ -4,7 +4,7 @@ define(['../string/escapeRegExp', '../internal/isObjectLike'], function(escapeRe
   var funcTag = '[object Function]';
 
   /** Used to detect host constructors (Safari > 5). */
-  var reHostCtor = /^\[object .+?Constructor\]$/;
+  var reIsHostCtor = /^\[object .+?Constructor\]$/;
 
   /** Used for native method references. */
   var objectProto = Object.prototype;
@@ -19,7 +19,7 @@ define(['../string/escapeRegExp', '../internal/isObjectLike'], function(escapeRe
   var objToString = objectProto.toString;
 
   /** Used to detect if a method is native. */
-  var reNative = RegExp('^' +
+  var reIsNative = RegExp('^' +
     escapeRegExp(objToString)
     .replace(/toString|(function).*?(?=\\\()| for .+?(?=\\\])/g, '$1.*?') + '$'
   );
@@ -45,9 +45,9 @@ define(['../string/escapeRegExp', '../internal/isObjectLike'], function(escapeRe
       return false;
     }
     if (objToString.call(value) == funcTag) {
-      return reNative.test(fnToString.call(value));
+      return reIsNative.test(fnToString.call(value));
     }
-    return isObjectLike(value) && reHostCtor.test(value);
+    return isObjectLike(value) && reIsHostCtor.test(value);
   }
 
   return isNative;

lang/isUndefined.js

@@ -1,5 +1,8 @@
 define([], function() {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /**
    * Checks if `value` is `undefined`.
    *
@@ -17,7 +20,7 @@ define([], function() {
    * // => false
    */
   function isUndefined(value) {
-    return typeof value == 'undefined';
+    return value === undefined;
   }
 
   return isUndefined;

lang/toArray.js

@@ -1,4 +1,4 @@
-define(['../internal/arrayCopy', '../internal/isLength', '../object/values'], function(arrayCopy, isLength, values) {
+define(['../internal/arrayCopy', '../internal/getLength', '../internal/isLength', '../object/values'], function(arrayCopy, getLength, isLength, values) {
 
   /**
    * Converts `value` to an array.
@@ -16,7 +16,7 @@ define(['../internal/arrayCopy', '../internal/isLength', '../object/values'], fu
    * // => [2, 3]
    */
   function toArray(value) {
-    var length = value ? value.length : 0;
+    var length = value ? getLength(value) : 0;
     if (!isLength(length)) {
       return values(value);
     }

math/add.js

@@ -15,7 +15,7 @@ define([], function() {
    * // => 10
    */
   function add(augend, addend) {
-    return augend + addend;
+    return (+augend || 0) + (+addend || 0);
   }
 
   return add;

number/inRange.js

@@ -1,5 +1,9 @@
 define([], function() {
 
+  /* Native method references for those with the same name as other `lodash` methods. */
+  var nativeMax = Math.max,
+      nativeMin = Math.min;
+
   /**
    * Checks if `n` is between `start` and up to but not including, `end`. If
    * `end` is not specified it is set to `start` with `start` then set to `0`.
@@ -39,7 +43,7 @@ define([], function() {
     } else {
       end = +end || 0;
     }
-    return value >= start && value < end;
+    return value >= nativeMin(start, end) && value < nativeMax(start, end);
   }
 
   return inRange;

object.js

@@ -1,4 +1,4 @@
-define(['./object/assign', './object/create', './object/defaults', './object/extend', './object/findKey', './object/findLastKey', './object/forIn', './object/forInRight', './object/forOwn', './object/forOwnRight', './object/functions', './object/has', './object/invert', './object/keys', './object/keysIn', './object/mapValues', './object/merge', './object/methods', './object/omit', './object/pairs', './object/pick', './object/result', './object/transform', './object/values', './object/valuesIn'], function(assign, create, defaults, extend, findKey, findLastKey, forIn, forInRight, forOwn, forOwnRight, functions, has, invert, keys, keysIn, mapValues, merge, methods, omit, pairs, pick, result, transform, values, valuesIn) {
+define(['./object/assign', './object/create', './object/defaults', './object/extend', './object/findKey', './object/findLastKey', './object/forIn', './object/forInRight', './object/forOwn', './object/forOwnRight', './object/functions', './object/get', './object/has', './object/invert', './object/keys', './object/keysIn', './object/mapValues', './object/merge', './object/methods', './object/omit', './object/pairs', './object/pick', './object/result', './object/set', './object/transform', './object/values', './object/valuesIn'], function(assign, create, defaults, extend, findKey, findLastKey, forIn, forInRight, forOwn, forOwnRight, functions, get, has, invert, keys, keysIn, mapValues, merge, methods, omit, pairs, pick, result, set, transform, values, valuesIn) {
   return {
     'assign': assign,
     'create': create,
@@ -11,6 +11,7 @@ define(['./object/assign', './object/create', './object/defaults', './object/ext
     'forOwn': forOwn,
     'forOwnRight': forOwnRight,
     'functions': functions,
+    'get': get,
     'has': has,
     'invert': invert,
     'keys': keys,
@@ -22,6 +23,7 @@ define(['./object/assign', './object/create', './object/defaults', './object/ext
     'pairs': pairs,
     'pick': pick,
     'result': result,
+    'set': set,
     'transform': transform,
     'values': values,
     'valuesIn': valuesIn

object/assign.js

@@ -1,4 +1,4 @@
-define(['../internal/baseAssign', '../internal/createAssigner'], function(baseAssign, createAssigner) {
+define(['../internal/assignWith', '../internal/baseAssign', '../internal/createAssigner'], function(assignWith, baseAssign, createAssigner) {
 
   /**
    * Assigns own enumerable properties of source object(s) to the destination
@@ -7,13 +7,17 @@ define(['../internal/baseAssign', '../internal/createAssigner'], function(baseAs
    * The `customizer` is bound to `thisArg` and invoked with five arguments:
    * (objectValue, sourceValue, key, object, source).
    *
+   * **Note:** This method mutates `object` and is based on
+   * [`Object.assign`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.assign).
+   *
+   *
    * @static
    * @memberOf _
    * @alias extend
    * @category Object
    * @param {Object} object The destination object.
    * @param {...Object} [sources] The source objects.
-   * @param {Function} [customizer] The function to customize assigning values.
+   * @param {Function} [customizer] The function to customize assigned values.
    * @param {*} [thisArg] The `this` binding of `customizer`.
    * @returns {Object} Returns `object`.
    * @example
@@ -23,13 +27,17 @@ define(['../internal/baseAssign', '../internal/createAssigner'], function(baseAs
    *
    * // using a customizer callback
    * var defaults = _.partialRight(_.assign, function(value, other) {
-   *   return typeof value == 'undefined' ? other : value;
+   *   return _.isUndefined(value) ? other : value;
    * });
    *
    * defaults({ 'user': 'barney' }, { 'age': 36 }, { 'user': 'fred' });
    * // => { 'user': 'barney', 'age': 36 }
    */
-  var assign = createAssigner(baseAssign);
+  var assign = createAssigner(function(object, source, customizer) {
+    return customizer
+      ? assignWith(object, source, customizer)
+      : baseAssign(object, source);
+  });
 
   return assign;
 });

object/create.js

@@ -1,4 +1,4 @@
-define(['../internal/baseCopy', '../internal/baseCreate', '../internal/isIterateeCall', './keys'], function(baseCopy, baseCreate, isIterateeCall, keys) {
+define(['../internal/baseAssign', '../internal/baseCreate', '../internal/isIterateeCall'], function(baseAssign, baseCreate, isIterateeCall) {
 
   /**
    * Creates an object that inherits from the given `prototype` object. If a
@@ -39,7 +39,7 @@ define(['../internal/baseCopy', '../internal/baseCreate', '../internal/isIterate
     if (guard && isIterateeCall(prototype, properties, guard)) {
       properties = null;
     }
-    return properties ? baseCopy(properties, result, keys(properties)) : result;
+    return properties ? baseAssign(result, properties) : result;
   }
 
   return create;

object/defaults.js

@@ -8,6 +8,8 @@ define(['./assign', '../internal/assignDefaults', '../function/restParam'], func
    * object for all destination properties that resolve to `undefined`. Once a
    * property is set, additional values of the same property are ignored.
    *
+   * **Note:** This method mutates `object`.
+   *
    * @static
    * @memberOf _
    * @category Object

object/forIn.js

@@ -3,7 +3,7 @@ define(['../internal/baseFor', '../internal/createForIn'], function(baseFor, cre
   /**
    * Iterates over own and inherited enumerable properties of an object invoking
    * `iteratee` for each property. The `iteratee` is bound to `thisArg` and invoked
-   * with three arguments: (value, key, object). Iterator functions may exit
+   * with three arguments: (value, key, object). Iteratee functions may exit
    * iteration early by explicitly returning `false`.
    *
    * @static

object/forOwn.js

@@ -3,7 +3,7 @@ define(['../internal/baseForOwn', '../internal/createForOwn'], function(baseForO
   /**
    * Iterates over own enumerable properties of an object invoking `iteratee`
    * for each property. The `iteratee` is bound to `thisArg` and invoked with
-   * three arguments: (value, key, object). Iterator functions may exit iteration
+   * three arguments: (value, key, object). Iteratee functions may exit iteration
    * early by explicitly returning `false`.
    *
    * @static

object/get.js

@@ -0,0 +1,36 @@
+define(['../internal/baseGet', '../internal/toPath'], function(baseGet, toPath) {
+
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
+  /**
+   * Gets the property value of `path` on `object`. If the resolved value is
+   * `undefined` the `defaultValue` is used in its place.
+   *
+   * @static
+   * @memberOf _
+   * @category Object
+   * @param {Object} object The object to query.
+   * @param {Array|string} path The path of the property to get.
+   * @param {*} [defaultValue] The value returned if the resolved value is `undefined`.
+   * @returns {*} Returns the resolved value.
+   * @example
+   *
+   * var object = { 'a': [{ 'b': { 'c': 3 } }] };
+   *
+   * _.get(object, 'a[0].b.c');
+   * // => 3
+   *
+   * _.get(object, ['a', '0', 'b', 'c']);
+   * // => 3
+   *
+   * _.get(object, 'a.b.c', 'default');
+   * // => 'default'
+   */
+  function get(object, path, defaultValue) {
+    var result = object == null ? undefined : baseGet(object, toPath(path), path + '');
+    return result === undefined ? defaultValue : result;
+  }
+
+  return get;
+});

object/has.js

@@ -1,4 +1,4 @@
-define([], function() {
+define(['../internal/baseGet', '../internal/baseSlice', '../internal/isKey', '../array/last', '../internal/toPath'], function(baseGet, baseSlice, isKey, last, toPath) {
 
   /** Used for native method references. */
   var objectProto = Object.prototype;
@@ -7,24 +7,39 @@ define([], function() {
   var hasOwnProperty = objectProto.hasOwnProperty;
 
   /**
-   * Checks if `key` exists as a direct property of `object` instead of an
-   * inherited property.
+   * Checks if `path` is a direct property.
    *
    * @static
    * @memberOf _
    * @category Object
-   * @param {Object} object The object to inspect.
-   * @param {string} key The key to check.
-   * @returns {boolean} Returns `true` if `key` is a direct property, else `false`.
+   * @param {Object} object The object to query.
+   * @param {Array|string} path The path to check.
+   * @returns {boolean} Returns `true` if `path` is a direct property, else `false`.
    * @example
    *
-   * var object = { 'a': 1, 'b': 2, 'c': 3 };
+   * var object = { 'a': { 'b': { 'c': 3 } } };
    *
-   * _.has(object, 'b');
+   * _.has(object, 'a');
+   * // => true
+   *
+   * _.has(object, 'a.b.c');
+   * // => true
+   *
+   * _.has(object, ['a', 'b', 'c']);
    * // => true
    */
-  function has(object, key) {
-    return object ? hasOwnProperty.call(object, key) : false;
+  function has(object, path) {
+    if (object == null) {
+      return false;
+    }
+    var result = hasOwnProperty.call(object, path);
+    if (!result && !isKey(path)) {
+      path = toPath(path);
+      object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
+      path = last(path);
+      result = object != null && hasOwnProperty.call(object, path);
+    }
+    return result;
   }
 
   return has;

object/keys.js

@@ -13,7 +13,7 @@ define(['../internal/isLength', '../lang/isNative', '../lang/isObject', '../inte
    * @static
    * @memberOf _
    * @category Object
-   * @param {Object} object The object to inspect.
+   * @param {Object} object The object to query.
    * @returns {Array} Returns the array of property names.
    * @example
    *
@@ -36,7 +36,7 @@ define(['../internal/isLength', '../lang/isNative', '../lang/isObject', '../inte
           length = object.length;
     }
     if ((typeof Ctor == 'function' && Ctor.prototype === object) ||
-        (typeof object != 'function' && (length && isLength(length)))) {
+        (typeof object != 'function' && isLength(length))) {
       return shimKeys(object);
     }
     return isObject(object) ? nativeKeys(object) : [];

object/keysIn.js

@@ -14,7 +14,7 @@ define(['../lang/isArguments', '../lang/isArray', '../internal/isIndex', '../int
    * @static
    * @memberOf _
    * @category Object
-   * @param {Object} object The object to inspect.
+   * @param {Object} object The object to query.
    * @returns {Array} Returns the array of property names.
    * @example
    *

object/merge.js

@@ -14,7 +14,7 @@ define(['../internal/baseMerge', '../internal/createAssigner'], function(baseMer
    * @category Object
    * @param {Object} object The destination object.
    * @param {...Object} [sources] The source objects.
-   * @param {Function} [customizer] The function to customize merging properties.
+   * @param {Function} [customizer] The function to customize assigned values.
    * @param {*} [thisArg] The `this` binding of `customizer`.
    * @returns {Object} Returns `object`.
    * @example