Bump to v3.10.1.

README.md

@@ -1,4 +1,4 @@
-# lodash v3.6.0
+# lodash v3.10.1
 
 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#3.10.1-amd
+$ volo add lodash/3.10.1-amd
+```
+
 Defining a build as `'lodash'`.
 
 ```js

array.js

@@ -1,4 +1,4 @@
-define(['./array/chunk', './array/compact', './array/difference', './array/drop', './array/dropRight', './array/dropRightWhile', './array/dropWhile', './array/fill', './array/findIndex', './array/findLastIndex', './array/first', './array/flatten', './array/flattenDeep', './array/head', './array/indexOf', './array/initial', './array/intersection', './array/last', './array/lastIndexOf', './array/object', './array/pull', './array/pullAt', './array/remove', './array/rest', './array/slice', './array/sortedIndex', './array/sortedLastIndex', './array/tail', './array/take', './array/takeRight', './array/takeRightWhile', './array/takeWhile', './array/union', './array/uniq', './array/unique', './array/unzip', './array/without', './array/xor', './array/zip', './array/zipObject'], function(chunk, compact, difference, drop, dropRight, dropRightWhile, dropWhile, fill, findIndex, findLastIndex, first, flatten, flattenDeep, head, indexOf, initial, intersection, last, lastIndexOf, object, pull, pullAt, remove, rest, slice, sortedIndex, sortedLastIndex, tail, take, takeRight, takeRightWhile, takeWhile, union, uniq, unique, unzip, without, xor, zip, zipObject) {
+define(['./array/chunk', './array/compact', './array/difference', './array/drop', './array/dropRight', './array/dropRightWhile', './array/dropWhile', './array/fill', './array/findIndex', './array/findLastIndex', './array/first', './array/flatten', './array/flattenDeep', './array/head', './array/indexOf', './array/initial', './array/intersection', './array/last', './array/lastIndexOf', './array/object', './array/pull', './array/pullAt', './array/remove', './array/rest', './array/slice', './array/sortedIndex', './array/sortedLastIndex', './array/tail', './array/take', './array/takeRight', './array/takeRightWhile', './array/takeWhile', './array/union', './array/uniq', './array/unique', './array/unzip', './array/unzipWith', './array/without', './array/xor', './array/zip', './array/zipObject', './array/zipWith'], function(chunk, compact, difference, drop, dropRight, dropRightWhile, dropWhile, fill, findIndex, findLastIndex, first, flatten, flattenDeep, head, indexOf, initial, intersection, last, lastIndexOf, object, pull, pullAt, remove, rest, slice, sortedIndex, sortedLastIndex, tail, take, takeRight, takeRightWhile, takeWhile, union, uniq, unique, unzip, unzipWith, without, xor, zip, zipObject, zipWith) {
   return {
     'chunk': chunk,
     'compact': compact,
@@ -36,9 +36,11 @@ define(['./array/chunk', './array/compact', './array/difference', './array/drop'
     'uniq': uniq,
     'unique': unique,
     'unzip': unzip,
+    'unzipWith': unzipWith,
     'without': without,
     'xor': xor,
     'zip': zip,
-    'zipObject': zipObject
+    'zipObject': zipObject,
+    'zipWith': zipWith
   };
 });

array/chunk.js

@@ -1,10 +1,9 @@
 define(['../internal/baseSlice', '../internal/isIterateeCall'], function(baseSlice, isIterateeCall) {
 
-  /** Native method references. */
-  var ceil = Math.ceil;
-
   /* Native method references for those with the same name as other `lodash` methods. */
-  var nativeMax = Math.max;
+  var nativeCeil = Math.ceil,
+      nativeFloor = Math.floor,
+      nativeMax = Math.max;
 
   /**
    * Creates an array of elements split into groups the length of `size`.
@@ -30,12 +29,12 @@ define(['../internal/baseSlice', '../internal/isIterateeCall'], function(baseSli
     if (guard ? isIterateeCall(array, size, guard) : size == null) {
       size = 1;
     } else {
-      size = nativeMax(+size || 1, 1);
+      size = nativeMax(nativeFloor(size) || 1, 1);
     }
     var index = 0,
         length = array ? array.length : 0,
         resIndex = -1,
-        result = Array(ceil(length / size));
+        result = Array(nativeCeil(length / size));
 
     while (index < length) {
       result[++resIndex] = baseSlice(array, index, (index += size));

array/difference.js

@@ -1,12 +1,9 @@
-define(['../internal/baseDifference', '../internal/baseFlatten', '../lang/isArguments', '../lang/isArray', '../function/restParam'], function(baseDifference, baseFlatten, isArguments, isArray, restParam) {
+define(['../internal/baseDifference', '../internal/baseFlatten', '../internal/isArrayLike', '../internal/isObjectLike', '../function/restParam'], function(baseDifference, baseFlatten, isArrayLike, isObjectLike, restParam) {
 
   /**
-   * Creates an array excluding all values of the provided arrays using
-   * `SameValueZero` for equality comparisons.
-   *
-   * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
-   * comparisons are like strict equality comparisons, e.g. `===`, except that
-   * `NaN` matches `NaN`.
+   * Creates an array of unique `array` values not included in the other
+   * provided arrays using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+   * for equality comparisons.
    *
    * @static
    * @memberOf _
@@ -20,7 +17,7 @@ define(['../internal/baseDifference', '../internal/baseFlatten', '../lang/isArgu
    * // => [1, 3]
    */
   var difference = restParam(function(array, values) {
-    return (isArray(array) || isArguments(array))
+    return (isObjectLike(array) && isArrayLike(array))
       ? baseDifference(array, baseFlatten(values, false, true))
       : [];
   });

array/flatten.js

@@ -2,7 +2,7 @@ define(['../internal/baseFlatten', '../internal/isIterateeCall'], function(baseF
 
   /**
    * Flattens a nested array. If `isDeep` is `true` the array is recursively
-   * flattened, otherwise it is only flattened a single level.
+   * flattened, otherwise it's only flattened a single level.
    *
    * @static
    * @memberOf _

array/indexOf.js

@@ -5,13 +5,10 @@ define(['../internal/baseIndexOf', '../internal/binaryIndex'], function(baseInde
 
   /**
    * Gets the index at which the first occurrence of `value` is found in `array`
-   * using `SameValueZero` for equality comparisons. If `fromIndex` is negative,
-   * it is used as the offset from the end of `array`. If `array` is sorted
-   * providing `true` for `fromIndex` performs a faster binary search.
-   *
-   * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
-   * comparisons are like strict equality comparisons, e.g. `===`, except that
-   * `NaN` matches `NaN`.
+   * using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+   * for equality comparisons. If `fromIndex` is negative, it's used as the offset
+   * from the end of `array`. If `array` is sorted providing `true` for `fromIndex`
+   * performs a faster binary search.
    *
    * @static
    * @memberOf _
@@ -42,10 +39,9 @@ define(['../internal/baseIndexOf', '../internal/binaryIndex'], function(baseInde
     if (typeof fromIndex == 'number') {
       fromIndex = fromIndex < 0 ? nativeMax(length + fromIndex, 0) : fromIndex;
     } else if (fromIndex) {
-      var index = binaryIndex(array, value),
-          other = array[index];
-
-      if (value === value ? (value === other) : (other !== other)) {
+      var index = binaryIndex(array, value);
+      if (index < length &&
+          (value === value ? (value === array[index]) : (array[index] !== array[index]))) {
         return index;
       }
       return -1;

array/intersection.js

@@ -1,13 +1,10 @@
-define(['../internal/baseIndexOf', '../internal/cacheIndexOf', '../internal/createCache', '../lang/isArguments', '../lang/isArray'], function(baseIndexOf, cacheIndexOf, createCache, isArguments, isArray) {
+define(['../internal/baseIndexOf', '../internal/cacheIndexOf', '../internal/createCache', '../internal/isArrayLike', '../function/restParam'], function(baseIndexOf, cacheIndexOf, createCache, isArrayLike, restParam) {
 
   /**
-   * Creates an array of unique values in all provided arrays using `SameValueZero`
+   * Creates an array of unique values that are included in all of the provided
+   * arrays using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
    * for equality comparisons.
    *
-   * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
-   * comparisons are like strict equality comparisons, e.g. `===`, except that
-   * `NaN` matches `NaN`.
-   *
    * @static
    * @memberOf _
    * @category Array
@@ -17,36 +14,31 @@ define(['../internal/baseIndexOf', '../internal/cacheIndexOf', '../internal/crea
    * _.intersection([1, 2], [4, 2], [2, 1]);
    * // => [2]
    */
-  function intersection() {
-    var args = [],
-        argsIndex = -1,
-        argsLength = arguments.length,
-        caches = [],
+  var intersection = restParam(function(arrays) {
+    var othLength = arrays.length,
+        othIndex = othLength,
+        caches = Array(length),
         indexOf = baseIndexOf,
-        isCommon = true;
+        isCommon = true,
+        result = [];
 
-    while (++argsIndex < argsLength) {
-      var value = arguments[argsIndex];
-      if (isArray(value) || isArguments(value)) {
-        args.push(value);
-        caches.push((isCommon && value.length >= 120) ? createCache(argsIndex && value) : null);
-      }
+    while (othIndex--) {
+      var value = arrays[othIndex] = isArrayLike(value = arrays[othIndex]) ? value : [];
+      caches[othIndex] = (isCommon && value.length >= 120) ? createCache(othIndex && value) : null;
     }
-    argsLength = args.length;
-    var array = args[0],
+    var array = arrays[0],
         index = -1,
         length = array ? array.length : 0,
-        result = [],
         seen = caches[0];
 
     outer:
     while (++index < length) {
       value = array[index];
       if ((seen ? cacheIndexOf(seen, value) : indexOf(result, value, 0)) < 0) {
-        argsIndex = argsLength;
-        while (--argsIndex) {
-          var cache = caches[argsIndex];
-          if ((cache ? cacheIndexOf(cache, value) : indexOf(args[argsIndex], value, 0)) < 0) {
+        var othIndex = othLength;
+        while (--othIndex) {
+          var cache = caches[othIndex];
+          if ((cache ? cacheIndexOf(cache, value) : indexOf(arrays[othIndex], value, 0)) < 0) {
             continue outer;
           }
         }
@@ -57,7 +49,7 @@ define(['../internal/baseIndexOf', '../internal/cacheIndexOf', '../internal/crea
       }
     }
     return result;
-  }
+  });
 
   return intersection;
 });

array/pull.js

@@ -7,14 +7,11 @@ define(['../internal/baseIndexOf'], function(baseIndexOf) {
   var splice = arrayProto.splice;
 
   /**
-   * Removes all provided values from `array` using `SameValueZero` for equality
-   * comparisons.
+   * Removes all provided values from `array` using
+   * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+   * for equality comparisons.
    *
-   * **Notes:**
-   *  - Unlike `_.without`, this method mutates `array`
-   *  - [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
-   *    comparisons are like strict equality comparisons, e.g. `===`, except
-   *    that `NaN` matches `NaN`
+   * **Note:** Unlike `_.without`, this method mutates `array`.
    *
    * @static
    * @memberOf _

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
@@ -32,20 +26,10 @@ define(['../internal/baseAt', '../internal/baseCompareAscending', '../internal/b
    * // => [10, 20]
    */
   var pullAt = restParam(function(array, indexes) {
-    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/sortedIndex.js

@@ -3,7 +3,7 @@ define(['../internal/createSortedIndex'], function(createSortedIndex) {
   /**
    * Uses a binary search to determine the lowest index at which `value` should
    * be inserted into `array` in order to maintain its sort order. If an iteratee
-   * function is provided it is invoked for `value` and each element of `array`
+   * function is provided it's invoked for `value` and each element of `array`
    * to compute their sort ranking. The iteratee is bound to `thisArg` and
    * invoked with one argument; (value).
    *

array/union.js

@@ -1,12 +1,9 @@
 define(['../internal/baseFlatten', '../internal/baseUniq', '../function/restParam'], function(baseFlatten, baseUniq, restParam) {
 
   /**
-   * Creates an array of unique values, in order, of the provided arrays using
-   * `SameValueZero` for equality comparisons.
-   *
-   * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
-   * comparisons are like strict equality comparisons, e.g. `===`, except that
-   * `NaN` matches `NaN`.
+   * Creates an array of unique values, in order, from all of the provided arrays
+   * using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+   * for equality comparisons.
    *
    * @static
    * @memberOf _

array/uniq.js

@@ -1,12 +1,17 @@
 define(['../internal/baseCallback', '../internal/baseUniq', '../internal/isIterateeCall', '../internal/sortedUniq'], function(baseCallback, baseUniq, isIterateeCall, sortedUniq) {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /**
-   * 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`](http://ecma-international.org/ecma-262/6.0/#sec-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's 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.
@@ -19,10 +24,6 @@ define(['../internal/baseCallback', '../internal/baseUniq', '../internal/isItera
    * callback returns `true` for elements that have the properties of the given
    * object, else `false`.
    *
-   * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
-   * comparisons are like strict equality comparisons, e.g. `===`, except that
-   * `NaN` matches `NaN`.
-   *
    * @static
    * @memberOf _
    * @alias unique
@@ -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);
@@ -58,7 +59,7 @@ define(['../internal/baseCallback', '../internal/baseUniq', '../internal/isItera
     }
     if (isSorted != null && typeof isSorted != 'boolean') {
       thisArg = iteratee;
-      iteratee = isIterateeCall(array, isSorted, thisArg) ? null : isSorted;
+      iteratee = isIterateeCall(array, isSorted, thisArg) ? undefined : isSorted;
       isSorted = false;
     }
     iteratee = iteratee == null ? iteratee : baseCallback(iteratee, thisArg, 3);

array/unzip.js

@@ -1,11 +1,11 @@
-define(['../internal/arrayMap', '../internal/arrayMax', '../internal/baseProperty'], function(arrayMap, arrayMax, baseProperty) {
+define(['../internal/arrayFilter', '../internal/arrayMap', '../internal/baseProperty', '../internal/isArrayLike'], function(arrayFilter, arrayMap, baseProperty, isArrayLike) {
 
-  /** Used to the length of n-tuples for `_.unzip`. */
-  var getLength = baseProperty('length');
+  /* Native method references for those with the same name as other `lodash` methods. */
+  var nativeMax = Math.max;
 
   /**
    * This method is like `_.zip` except that it accepts an array of grouped
-   * elements and creates an array regrouping the elements to their pre-`_.zip`
+   * elements and creates an array regrouping the elements to their pre-zip
    * configuration.
    *
    * @static
@@ -22,10 +22,19 @@ define(['../internal/arrayMap', '../internal/arrayMax', '../internal/basePropert
    * // => [['fred', 'barney'], [30, 40], [true, false]]
    */
   function unzip(array) {
+    if (!(array && array.length)) {
+      return [];
+    }
     var index = -1,
-        length = (array && array.length && arrayMax(arrayMap(array, getLength))) >>> 0,
-        result = Array(length);
+        length = 0;
 
+    array = arrayFilter(array, function(group) {
+      if (isArrayLike(group)) {
+        length = nativeMax(group.length, length);
+        return true;
+      }
+    });
+    var result = Array(length);
     while (++index < length) {
       result[index] = arrayMap(array, baseProperty(index));
     }

array/unzipWith.js

@@ -0,0 +1,42 @@
+define(['../internal/arrayMap', '../internal/arrayReduce', '../internal/bindCallback', './unzip'], function(arrayMap, arrayReduce, bindCallback, unzip) {
+
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
+  /**
+   * This method is like `_.unzip` except that it accepts an iteratee to specify
+   * how regrouped values should be combined. The `iteratee` is bound to `thisArg`
+   * and invoked with four arguments: (accumulator, value, index, group).
+   *
+   * @static
+   * @memberOf _
+   * @category Array
+   * @param {Array} array The array of grouped elements to process.
+   * @param {Function} [iteratee] The function to combine regrouped values.
+   * @param {*} [thisArg] The `this` binding of `iteratee`.
+   * @returns {Array} Returns the new array of regrouped elements.
+   * @example
+   *
+   * var zipped = _.zip([1, 2], [10, 20], [100, 200]);
+   * // => [[1, 10, 100], [2, 20, 200]]
+   *
+   * _.unzipWith(zipped, _.add);
+   * // => [3, 30, 300]
+   */
+  function unzipWith(array, iteratee, thisArg) {
+    var length = array ? array.length : 0;
+    if (!length) {
+      return [];
+    }
+    var result = unzip(array);
+    if (iteratee == null) {
+      return result;
+    }
+    iteratee = bindCallback(iteratee, thisArg, 4);
+    return arrayMap(result, function(group) {
+      return arrayReduce(group, iteratee, undefined, true);
+    });
+  }
+
+  return unzipWith;
+});

array/without.js

@@ -1,12 +1,9 @@
-define(['../internal/baseDifference', '../lang/isArguments', '../lang/isArray', '../function/restParam'], function(baseDifference, isArguments, isArray, restParam) {
+define(['../internal/baseDifference', '../internal/isArrayLike', '../function/restParam'], function(baseDifference, isArrayLike, restParam) {
 
   /**
-   * Creates an array excluding all provided values using `SameValueZero` for
-   * equality comparisons.
-   *
-   * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
-   * comparisons are like strict equality comparisons, e.g. `===`, except that
-   * `NaN` matches `NaN`.
+   * Creates an array excluding all provided values using
+   * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+   * for equality comparisons.
    *
    * @static
    * @memberOf _
@@ -20,7 +17,7 @@ define(['../internal/baseDifference', '../lang/isArguments', '../lang/isArray',
    * // => [3]
    */
   var without = restParam(function(array, values) {
-    return (isArray(array) || isArguments(array))
+    return isArrayLike(array)
       ? baseDifference(array, values)
       : [];
   });

array/xor.js

@@ -1,7 +1,7 @@
-define(['../internal/baseDifference', '../internal/baseUniq', '../lang/isArguments', '../lang/isArray'], function(baseDifference, baseUniq, isArguments, isArray) {
+define(['../internal/arrayPush', '../internal/baseDifference', '../internal/baseUniq', '../internal/isArrayLike'], function(arrayPush, baseDifference, baseUniq, isArrayLike) {
 
   /**
-   * Creates an array that is the [symmetric difference](https://en.wikipedia.org/wiki/Symmetric_difference)
+   * Creates an array of unique values that is the [symmetric difference](https://en.wikipedia.org/wiki/Symmetric_difference)
    * of the provided arrays.
    *
    * @static
@@ -20,9 +20,9 @@ define(['../internal/baseDifference', '../internal/baseUniq', '../lang/isArgumen
 
     while (++index < length) {
       var array = arguments[index];
-      if (isArray(array) || isArguments(array)) {
+      if (isArrayLike(array)) {
         var result = result
-          ? baseDifference(result, array).concat(baseDifference(array, result))
+          ? arrayPush(baseDifference(result, array), baseDifference(array, result))
           : array;
       }
     }

array/zipWith.js

@@ -0,0 +1,39 @@
+define(['../function/restParam', './unzipWith'], function(restParam, unzipWith) {
+
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
+  /**
+   * This method is like `_.zip` except that it accepts an iteratee to specify
+   * how grouped values should be combined. The `iteratee` is bound to `thisArg`
+   * and invoked with four arguments: (accumulator, value, index, group).
+   *
+   * @static
+   * @memberOf _
+   * @category Array
+   * @param {...Array} [arrays] The arrays to process.
+   * @param {Function} [iteratee] The function to combine grouped values.
+   * @param {*} [thisArg] The `this` binding of `iteratee`.
+   * @returns {Array} Returns the new array of grouped elements.
+   * @example
+   *
+   * _.zipWith([1, 2], [10, 20], [100, 200], _.add);
+   * // => [111, 222]
+   */
+  var zipWith = restParam(function(arrays) {
+    var length = arrays.length,
+        iteratee = length > 2 ? arrays[length - 2] : undefined,
+        thisArg = length > 1 ? arrays[length - 1] : undefined;
+
+    if (length > 2 && typeof iteratee == 'function') {
+      length -= 2;
+    } else {
+      iteratee = (length > 1 && typeof thisArg == 'function') ? (--length, thisArg) : undefined;
+      thisArg = undefined;
+    }
+    arrays.length = length;
+    return unzipWith(arrays, iteratee, thisArg);
+  });
+
+  return zipWith;
+});

chain.js

@@ -1,7 +1,8 @@
-define(['./chain/chain', './chain/commit', './chain/lodash', './chain/plant', './chain/reverse', './chain/run', './chain/tap', './chain/thru', './chain/toJSON', './chain/toString', './chain/value', './chain/valueOf', './chain/wrapperChain'], function(chain, commit, lodash, plant, reverse, run, tap, thru, toJSON, toString, value, valueOf, wrapperChain) {
+define(['./chain/chain', './chain/commit', './chain/concat', './chain/lodash', './chain/plant', './chain/reverse', './chain/run', './chain/tap', './chain/thru', './chain/toJSON', './chain/toString', './chain/value', './chain/valueOf', './chain/wrapperChain'], function(chain, commit, concat, lodash, plant, reverse, run, tap, thru, toJSON, toString, value, valueOf, wrapperChain) {
   return {
     'chain': chain,
     'commit': commit,
+    'concat': concat,
     'lodash': lodash,
     'plant': plant,
     'reverse': reverse,

chain/concat.js

@@ -0,0 +1,3 @@
+define(["./wrapperConcat"], function(wrapperConcat) {
+  return wrapperConcat;
+});

chain/lodash.js

@@ -9,15 +9,16 @@ define(['../internal/LazyWrapper', '../internal/LodashWrapper', '../internal/bas
   /**
    * Creates a `lodash` object which wraps `value` to enable implicit chaining.
    * Methods that operate on and return arrays, collections, and functions can
-   * be chained together. Methods that return a boolean or single value will
-   * automatically end the chain returning the unwrapped value. Explicit chaining
-   * may be enabled using `_.chain`. The execution of chained methods is lazy,
-   * that is, execution is deferred until `_#value` is implicitly or explicitly
-   * called.
+   * be chained together. Methods that retrieve a single value or may return a
+   * primitive value will automatically end the chain returning the unwrapped
+   * value. Explicit chaining may be enabled using `_.chain`. The execution of
+   * chained methods is lazy, that is, execution is deferred until `_#value`
+   * is implicitly or explicitly called.
    *
    * Lazy evaluation allows several methods to support shortcut fusion. Shortcut
-   * fusion is an optimization that merges iteratees to avoid creating intermediate
-   * arrays and reduce the number of iteratee executions.
+   * fusion is an optimization strategy which merge iteratee calls; this can help
+   * to avoid the creation of intermediate data structures and greatly reduce the
+   * number of iteratee executions.
    *
    * Chaining is supported in custom builds as long as the `_#value` method is
    * directly or indirectly included in the build.
@@ -40,35 +41,37 @@ define(['../internal/LazyWrapper', '../internal/LodashWrapper', '../internal/bas
    * The chainable wrapper methods are:
    * `after`, `ary`, `assign`, `at`, `before`, `bind`, `bindAll`, `bindKey`,
    * `callback`, `chain`, `chunk`, `commit`, `compact`, `concat`, `constant`,
-   * `countBy`, `create`, `curry`, `debounce`, `defaults`, `defer`, `delay`,
-   * `difference`, `drop`, `dropRight`, `dropRightWhile`, `dropWhile`, `fill`,
-   * `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`,
+   * `countBy`, `create`, `curry`, `debounce`, `defaults`, `defaultsDeep`,
+   * `defer`, `delay`, `difference`, `drop`, `dropRight`, `dropRightWhile`,
+   * `dropWhile`, `fill`, `filter`, `flatten`, `flattenDeep`, `flow`, `flowRight`,
+   * `forEach`, `forEachRight`, `forIn`, `forInRight`, `forOwn`, `forOwnRight`,
+   * `functions`, `groupBy`, `indexBy`, `initial`, `intersection`, `invert`,
+   * `invoke`, `keys`, `keysIn`, `map`, `mapKeys`, `mapValues`, `matches`,
+   * `matchesProperty`, `memoize`, `merge`, `method`, `methodOf`, `mixin`,
+   * `modArgs`, `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`,
-   * `spread`, `take`, `takeRight`, `takeRightWhile`, `takeWhile`, `tap`,
-   * `throttle`, `thru`, `times`, `toArray`, `toPlainObject`, `transform`,
-   * `union`, `uniq`, `unshift`, `unzip`, `values`, `valuesIn`, `where`,
-   * `without`, `wrap`, `xor`, `zip`, and `zipObject`
+   * `pullAt`, `push`, `range`, `rearg`, `reject`, `remove`, `rest`, `restParam`,
+   * `reverse`, `set`, `shuffle`, `slice`, `sort`, `sortBy`, `sortByAll`,
+   * `sortByOrder`, `splice`, `spread`, `take`, `takeRight`, `takeRightWhile`,
+   * `takeWhile`, `tap`, `throttle`, `thru`, `times`, `toArray`, `toPlainObject`,
+   * `transform`, `union`, `uniq`, `unshift`, `unzip`, `unzipWith`, `values`,
+   * `valuesIn`, `where`, `without`, `wrap`, `xor`, `zip`, `zipObject`, `zipWith`
    *
    * The wrapper methods that are **not** chainable by default are:
-   * `add`, `attempt`, `camelCase`, `capitalize`, `clone`, `cloneDeep`, `deburr`,
-   * `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`
+   * `add`, `attempt`, `camelCase`, `capitalize`, `ceil`, `clone`, `cloneDeep`,
+   * `deburr`, `endsWith`, `escape`, `escapeRegExp`, `every`, `find`, `findIndex`,
+   * `findKey`, `findLast`, `findLastIndex`, `findLastKey`, `findWhere`, `first`,
+   * `floor`, `get`, `gt`, `gte`, `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`, `lt`, `lte`, `max`, `min`, `noConflict`, `noop`,
+   * `now`, `pad`, `padLeft`, `padRight`, `parseInt`, `pop`, `random`, `reduce`,
+   * `reduceRight`, `repeat`, `result`, `round`, `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 +86,8 @@ 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
    *

chain/wrapperCommit.js

@@ -10,16 +10,16 @@ define(['../internal/LodashWrapper'], function(LodashWrapper) {
    * @example
    *
    * var array = [1, 2];
-   * var wrapper = _(array).push(3);
+   * var wrapped = _(array).push(3);
    *
    * console.log(array);
    * // => [1, 2]
    *
-   * wrapper = wrapper.commit();
+   * wrapped = wrapped.commit();
    * console.log(array);
    * // => [1, 2, 3]
    *
-   * wrapper.last();
+   * wrapped.last();
    * // => 3
    *
    * console.log(array);

chain/wrapperConcat.js

@@ -0,0 +1,31 @@
+define(['../internal/arrayConcat', '../internal/baseFlatten', '../lang/isArray', '../function/restParam', '../internal/toObject'], function(arrayConcat, baseFlatten, isArray, restParam, toObject) {
+
+  /**
+   * Creates a new array joining a wrapped array with any additional arrays
+   * and/or values.
+   *
+   * @name concat
+   * @memberOf _
+   * @category Chain
+   * @param {...*} [values] The values to concatenate.
+   * @returns {Array} Returns the new concatenated array.
+   * @example
+   *
+   * var array = [1];
+   * var wrapped = _(array).concat(2, [3], [[4]]);
+   *
+   * console.log(wrapped.value());
+   * // => [1, 2, 3, [4]]
+   *
+   * console.log(array);
+   * // => [1]
+   */
+  var wrapperConcat = restParam(function(values) {
+    values = baseFlatten(values);
+    return this.thru(function(array) {
+      return arrayConcat(isArray(array) ? array : [toObject(array)], values);
+    });
+  });
+
+  return wrapperConcat;
+});

chain/wrapperPlant.js

@@ -10,17 +10,17 @@ define(['../internal/baseLodash', '../internal/wrapperClone'], function(baseLoda
    * @example
    *
    * var array = [1, 2];
-   * var wrapper = _(array).map(function(value) {
+   * var wrapped = _(array).map(function(value) {
    *   return Math.pow(value, 2);
    * });
    *
    * var other = [3, 4];
-   * var otherWrapper = wrapper.plant(other);
+   * var otherWrapped = wrapped.plant(other);
    *
-   * otherWrapper.value();
+   * otherWrapped.value();
    * // => [9, 16]
    *
-   * wrapper.value();
+   * wrapped.value();
    * // => [1, 4]
    */
   function wrapperPlant(value) {

chain/wrapperReverse.js

@@ -1,5 +1,8 @@
 define(['../internal/LazyWrapper', '../internal/LodashWrapper', './thru'], function(LazyWrapper, LodashWrapper, thru) {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /**
    * Reverses the wrapped array so the first element becomes the last, the
    * second element becomes the second to last, and so on.
@@ -22,15 +25,20 @@ define(['../internal/LazyWrapper', '../internal/LodashWrapper', './thru'], funct
    */
   function wrapperReverse() {
     var value = this.__wrapped__;
-    if (value instanceof LazyWrapper) {
-      if (this.__actions__.length) {
-        value = new LazyWrapper(this);
-      }
-      return new LodashWrapper(value.reverse(), this.__chain__);
-    }
-    return this.thru(function(value) {
+
+    var interceptor = function(value) {
       return value.reverse();
-    });
+    };
+    if (value instanceof LazyWrapper) {
+      var wrapped = value;
+      if (this.__actions__.length) {
+        wrapped = new LazyWrapper(this);
+      }
+      wrapped = wrapped.reverse();
+      wrapped.__actions__.push({ 'func': thru, 'args': [interceptor], 'thisArg': undefined });
+      return new LodashWrapper(wrapped, this.__chain__);
+    }
+    return this.thru(interceptor);
   }
 
   return wrapperReverse;

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', '../function/restParam'], function(baseAt, baseFlatten, restParam) {
 
   /**
    * Creates an array of elements corresponding to the given keys, or indexes,
@@ -21,10 +21,6 @@ define(['../internal/baseAt', '../internal/baseFlatten', '../internal/isLength',
    * // => ['barney', 'pebbles']
    */
   var at = restParam(function(collection, props) {
-    var length = collection ? collection.length : 0;
-    if (isLength(length)) {
-      collection = toIterable(collection);
-    }
     return baseAt(collection, baseFlatten(props));
   });
 

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:
@@ -51,9 +54,9 @@ define(['../internal/arrayEvery', '../internal/baseCallback', '../internal/baseE
   function every(collection, predicate, thisArg) {
     var func = isArray(collection) ? arrayEvery : baseEvery;
     if (thisArg && isIterateeCall(collection, predicate, thisArg)) {
-      predicate = null;
+      predicate = undefined;
     }
-    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

@@ -1,16 +1,13 @@
-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;
 
   /**
-   * Checks if `value` is in `collection` using `SameValueZero` for equality
-   * comparisons. If `fromIndex` is negative, it is used as the offset from
-   * the end of `collection`.
-   *
-   * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
-   * comparisons are like strict equality comparisons, e.g. `===`, except that
-   * `NaN` matches `NaN`.
+   * Checks if `target` is in `collection` using
+   * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+   * for equality comparisons. If `fromIndex` is negative, it's used as the offset
+   * from the end of `collection`.
    *
    * @static
    * @memberOf _
@@ -36,22 +33,19 @@ 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;
     }
-    if (!length) {
-      return false;
-    }
     if (typeof fromIndex != 'number' || (guard && isIterateeCall(target, fromIndex, guard))) {
       fromIndex = 0;
     } else {
       fromIndex = fromIndex < 0 ? nativeMax(length + fromIndex, 0) : (fromIndex || 0);
     }
     return (typeof collection == 'string' || !isArray(collection) && isString(collection))
-      ? (fromIndex < length && collection.indexOf(target, fromIndex) > -1)
-      : (baseIndexOf(collection, target, fromIndex) > -1);
+      ? (fromIndex <= length && collection.indexOf(target, fromIndex) > -1)
+      : (!!length && baseIndexOf(collection, target, fromIndex) > -1);
   }
 
   return includes;

collection/invoke.js

@@ -1,19 +1,19 @@
-define(['../internal/baseEach', '../internal/isLength', '../function/restParam'], function(baseEach, isLength, restParam) {
+define(['../internal/baseEach', '../internal/invokePath', '../internal/isArrayLike', '../internal/isKey', '../function/restParam'], function(baseEach, invokePath, isArrayLike, isKey, restParam) {
 
   /** Used as a safe reference for `undefined` in pre-ES5 environments. */
   var undefined;
 
   /**
-   * 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` of 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's
+   * 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 +25,15 @@ 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,
-        result = isLength(length) ? Array(length) : [];
+        isFunc = typeof path == 'function',
+        isProp = isKey(path),
+        result = isArrayLike(collection) ? Array(collection.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] : undefined);
+      result[++index] = func ? func.apply(value, args) : invokePath(value, path, args);
     });
     return result;
   });

collection/map.js

@@ -16,14 +16,15 @@ define(['../internal/arrayMap', '../internal/baseCallback', '../internal/baseMap
    * callback returns `true` for elements that have the properties of the given
    * object, else `false`.
    *
-   * Many lodash methods are guarded to work as interatees for methods like
+   * Many lodash methods are guarded to work as iteratees for methods like
    * `_.every`, `_.filter`, `_.map`, `_.mapValues`, `_.reject`, and `_.some`.
    *
    * The guarded methods are:
-   * `ary`, `callback`, `chunk`, `clone`, `create`, `curry`, `curryRight`, `drop`,
-   * `dropRight`, `every`, `fill`, `flatten`, `invert`, `max`, `min`, `parseInt`,
-   * `slice`, `sortBy`, `take`, `takeRight`, `template`, `trim`, `trimLeft`,
-   * `trimRight`, `trunc`, `random`, `range`, `sample`, `some`, `uniq`, and `words`
+   * `ary`, `callback`, `chunk`, `clone`, `create`, `curry`, `curryRight`,
+   * `drop`, `dropRight`, `every`, `fill`, `flatten`, `invert`, `max`, `min`,
+   * `parseInt`, `slice`, `sortBy`, `take`, `takeRight`, `template`, `trim`,
+   * `trimLeft`, `trimRight`, `trunc`, `random`, `range`, `sample`, `some`,
+   * `sum`, `uniq`, and `words`
    *
    * @static
    * @memberOf _
@@ -32,7 +33,6 @@ 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

@@ -8,11 +8,12 @@ define(['../internal/arrayReduce', '../internal/baseEach', '../internal/createRe
    * value. The `iteratee` is bound to `thisArg` and invoked with four arguments:
    * (accumulator, value, index|key, collection).
    *
-   * Many lodash methods are guarded to work as interatees for methods like
+   * Many lodash methods are guarded to work as iteratees for methods like
    * `_.reduce`, `_.reduceRight`, and `_.transform`.
    *
    * The guarded methods are:
-   * `assign`, `defaults`, `includes`, `merge`, `sortByAll`, and `sortByOrder`
+   * `assign`, `defaults`, `defaultsDeep`, `includes`, `merge`, `sortByAll`,
+   * and `sortByOrder`
    *
    * @static
    * @memberOf _
@@ -25,8 +26,8 @@ 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/reduceRight.js

@@ -22,7 +22,7 @@ define(['../internal/arrayReduceRight', '../internal/baseEachRight', '../interna
    * }, []);
    * // => [4, 5, 2, 3, 0, 1]
    */
-  var reduceRight =  createReduce(arrayReduceRight, baseEachRight);
+  var reduceRight = createReduce(arrayReduceRight, baseEachRight);
 
   return reduceRight;
 });

collection/reject.js

@@ -4,17 +4,6 @@ define(['../internal/arrayFilter', '../internal/baseCallback', '../internal/base
    * The opposite of `_.filter`; this method returns the elements of `collection`
    * that `predicate` does **not** return truthy for.
    *
-   * If a property name is provided for `predicate` the created `_.property`
-   * style callback returns the property value of the given element.
-   *
-   * If a value is also provided for `thisArg` the created `_.matchesProperty`
-   * style callback returns `true` for elements that have a matching property
-   * value, else `false`.
-   *
-   * If an object is provided for `predicate` the created `_.matches` style
-   * callback returns `true` for elements that have the properties of the given
-   * object, else `false`.
-   *
    * @static
    * @memberOf _
    * @category Collection

collection/sample.js

@@ -1,4 +1,4 @@
-define(['../internal/baseRandom', '../internal/isIterateeCall', './shuffle', '../internal/toIterable'], function(baseRandom, isIterateeCall, shuffle, toIterable) {
+define(['../internal/baseRandom', '../internal/isIterateeCall', '../lang/toArray', '../internal/toIterable'], function(baseRandom, isIterateeCall, toArray, toIterable) {
 
   /** Used as a safe reference for `undefined` in pre-ES5 environments. */
   var undefined;
@@ -30,8 +30,20 @@ define(['../internal/baseRandom', '../internal/isIterateeCall', './shuffle', '..
       var length = collection.length;
       return length > 0 ? collection[baseRandom(0, length - 1)] : undefined;
     }
-    var result = shuffle(collection);
-    result.length = nativeMin(n < 0 ? 0 : (+n || 0), result.length);
+    var index = -1,
+        result = toArray(collection),
+        length = result.length,
+        lastIndex = length - 1;
+
+    n = nativeMin(n < 0 ? 0 : (+n || 0), length);
+    while (++index < n) {
+      var rand = baseRandom(index, lastIndex),
+          value = result[rand];
+
+      result[rand] = result[index];
+      result[index] = value;
+    }
+    result.length = n;
     return result;
   }
 

collection/shuffle.js

@@ -1,4 +1,7 @@
-define(['../internal/baseRandom', '../internal/toIterable'], function(baseRandom, toIterable) {
+define(['./sample'], function(sample) {
+
+  /** Used as references for `-Infinity` and `Infinity`. */
+  var POSITIVE_INFINITY = Number.POSITIVE_INFINITY;
 
   /**
    * Creates an array of shuffled values, using a version of the
@@ -15,20 +18,7 @@ define(['../internal/baseRandom', '../internal/toIterable'], function(baseRandom
    * // => [4, 1, 3, 2]
    */
   function shuffle(collection) {
-    collection = toIterable(collection);
-
-    var index = -1,
-        length = collection.length,
-        result = Array(length);
-
-    while (++index < length) {
-      var rand = baseRandom(0, index);
-      if (index != rand) {
-        result[index] = result[rand];
-      }
-      result[rand] = collection[index];
-    }
-    return result;
+    return sample(collection, POSITIVE_INFINITY);
   }
 
   return shuffle;

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
@@ -52,9 +55,9 @@ define(['../internal/arraySome', '../internal/baseCallback', '../internal/baseSo
   function some(collection, predicate, thisArg) {
     var func = isArray(collection) ? arraySome : baseSome;
     if (thisArg && isIterateeCall(collection, predicate, thisArg)) {
-      predicate = null;
+      predicate = undefined;
     }
-    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 +1,7 @@
-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) {
+
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
 
   /**
    * Creates an array of elements, sorted in ascending order by the results of
@@ -22,9 +25,8 @@ 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 +55,14 @@ 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;
+      iteratee = undefined;
     }
+    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

@@ -1,46 +1,56 @@
 define(['../internal/baseSortByOrder', '../lang/isArray', '../internal/isIterateeCall'], function(baseSortByOrder, isArray, isIterateeCall) {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /**
    * 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. If `orders` is unspecified, all
+   * values are sorted in ascending order. Otherwise, a value is sorted in
+   * ascending order if its corresponding order is "asc", and descending if "desc".
+   *
+   * 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]]
+   * _.map(_.sortByOrder(users, ['user', 'age'], ['asc', 'desc']), _.values);
+   * // => [['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)) {
-      orders = null;
+    if (guard && isIterateeCall(iteratees, orders, guard)) {
+      orders = undefined;
     }
-    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;

date/now.js

@@ -1,7 +1,7 @@
-define(['../lang/isNative'], function(isNative) {
+define(['../internal/getNative'], function(getNative) {
 
   /* Native method references for those with the same name as other `lodash` methods. */
-  var nativeNow = isNative(nativeNow = Date.now) && nativeNow;
+  var nativeNow = getNative(Date, 'now');
 
   /**
    * Gets the number of milliseconds that have elapsed since the Unix epoch

function.js

@@ -1,4 +1,4 @@
-define(['./function/after', './function/ary', './function/backflow', './function/before', './function/bind', './function/bindAll', './function/bindKey', './function/compose', './function/curry', './function/curryRight', './function/debounce', './function/defer', './function/delay', './function/flow', './function/flowRight', './function/memoize', './function/negate', './function/once', './function/partial', './function/partialRight', './function/rearg', './function/restParam', './function/spread', './function/throttle', './function/wrap'], function(after, ary, backflow, before, bind, bindAll, bindKey, compose, curry, curryRight, debounce, defer, delay, flow, flowRight, memoize, negate, once, partial, partialRight, rearg, restParam, spread, throttle, wrap) {
+define(['./function/after', './function/ary', './function/backflow', './function/before', './function/bind', './function/bindAll', './function/bindKey', './function/compose', './function/curry', './function/curryRight', './function/debounce', './function/defer', './function/delay', './function/flow', './function/flowRight', './function/memoize', './function/modArgs', './function/negate', './function/once', './function/partial', './function/partialRight', './function/rearg', './function/restParam', './function/spread', './function/throttle', './function/wrap'], function(after, ary, backflow, before, bind, bindAll, bindKey, compose, curry, curryRight, debounce, defer, delay, flow, flowRight, memoize, modArgs, negate, once, partial, partialRight, rearg, restParam, spread, throttle, wrap) {
   return {
     'after': after,
     'ary': ary,
@@ -16,6 +16,7 @@ define(['./function/after', './function/ary', './function/backflow', './function
     'flow': flow,
     'flowRight': flowRight,
     'memoize': memoize,
+    'modArgs': modArgs,
     'negate': negate,
     'once': once,
     'partial': partial,

function/after.js

@@ -8,7 +8,7 @@ define(['../internal/root'], function(root) {
 
   /**
    * The opposite of `_.before`; this method creates a function that invokes
-   * `func` once it is called `n` or more times.
+   * `func` once it's called `n` or more times.
    *
    * @static
    * @memberOf _

function/ary.js

@@ -1,5 +1,8 @@
 define(['../internal/createWrapper', '../internal/isIterateeCall'], function(createWrapper, isIterateeCall) {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /** Used to compose bitmasks for wrapper metadata. */
   var ARY_FLAG = 128;
 
@@ -24,10 +27,10 @@ define(['../internal/createWrapper', '../internal/isIterateeCall'], function(cre
    */
   function ary(func, n, guard) {
     if (guard && isIterateeCall(func, n, guard)) {
-      n = null;
+      n = undefined;
     }
     n = (func && n == null) ? func.length : nativeMax(+n || 0, 0);
-    return createWrapper(func, ARY_FLAG, null, null, null, null, n);
+    return createWrapper(func, ARY_FLAG, undefined, undefined, undefined, undefined, n);
   }
 
   return ary;

function/before.js

@@ -1,11 +1,14 @@
 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';
 
   /**
    * Creates a function that invokes `func`, with the `this` binding and arguments
-   * of the created function, while it is called less than `n` times. Subsequent
+   * of the created function, while it's called less than `n` times. Subsequent
    * calls to the created function return the result of the last `func` invocation.
    *
    * @static
@@ -33,8 +36,9 @@ define([], function() {
     return function() {
       if (--n > 0) {
         result = func.apply(this, arguments);
-      } else {
-        func = null;
+      }
+      if (n <= 1) {
+        func = undefined;
       }
       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/debounce.js

@@ -10,12 +10,13 @@ define(['../lang/isObject', '../date/now'], function(isObject, now) {
   var nativeMax = Math.max;
 
   /**
-   * Creates a function that delays invoking `func` until after `wait` milliseconds
-   * have elapsed since the last time it was invoked. The created function comes
-   * with a `cancel` method to cancel delayed invocations. Provide an options
-   * object to indicate that `func` should be invoked on the leading and/or
-   * trailing edge of the `wait` timeout. Subsequent calls to the debounced
-   * function return the result of the last `func` invocation.
+   * Creates a debounced function that delays invoking `func` until after `wait`
+   * milliseconds have elapsed since the last time the debounced function was
+   * invoked. The debounced function comes with a `cancel` method to cancel
+   * delayed invocations. Provide an options object to indicate that `func`
+   * should be invoked on the leading and/or trailing edge of the `wait` timeout.
+   * Subsequent calls to the debounced function return the result of the last
+   * `func` invocation.
    *
    * **Note:** If `leading` and `trailing` options are `true`, `func` is invoked
    * on the trailing edge of the timeout only if the the debounced function is
@@ -33,7 +34,7 @@ define(['../lang/isObject', '../date/now'], function(isObject, now) {
    * @param {boolean} [options.leading=false] Specify invoking on the leading
    *  edge of the timeout.
    * @param {number} [options.maxWait] The maximum time `func` is allowed to be
-   *  delayed before it is invoked.
+   *  delayed before it's invoked.
    * @param {boolean} [options.trailing=true] Specify invoking on the trailing
    *  edge of the timeout.
    * @returns {Function} Returns the new debounced function.
@@ -91,9 +92,9 @@ define(['../lang/isObject', '../date/now'], function(isObject, now) {
       var leading = true;
       trailing = false;
     } else if (isObject(options)) {
-      leading = options.leading;
+      leading = !!options.leading;
       maxWait = 'maxWait' in options && nativeMax(+options.maxWait || 0, wait);
-      trailing = 'trailing' in options ? options.trailing : trailing;
+      trailing = 'trailing' in options ? !!options.trailing : trailing;
     }
 
     function cancel() {
@@ -103,41 +104,35 @@ define(['../lang/isObject', '../date/now'], function(isObject, now) {
       if (maxTimeoutId) {
         clearTimeout(maxTimeoutId);
       }
+      lastCalled = 0;
       maxTimeoutId = timeoutId = trailingCall = undefined;
     }
 
+    function complete(isCalled, id) {
+      if (id) {
+        clearTimeout(id);
+      }
+      maxTimeoutId = timeoutId = trailingCall = undefined;
+      if (isCalled) {
+        lastCalled = now();
+        result = func.apply(thisArg, args);
+        if (!timeoutId && !maxTimeoutId) {
+          args = thisArg = undefined;
+        }
+      }
+    }
+
     function delayed() {
       var remaining = wait - (now() - stamp);
       if (remaining <= 0 || remaining > wait) {
-        if (maxTimeoutId) {
-          clearTimeout(maxTimeoutId);
-        }
-        var isCalled = trailingCall;
-        maxTimeoutId = timeoutId = trailingCall = undefined;
-        if (isCalled) {
-          lastCalled = now();
-          result = func.apply(thisArg, args);
-          if (!timeoutId && !maxTimeoutId) {
-            args = thisArg = null;
-          }
-        }
+        complete(trailingCall, maxTimeoutId);
       } else {
         timeoutId = setTimeout(delayed, remaining);
       }
     }
 
     function maxDelayed() {
-      if (timeoutId) {
-        clearTimeout(timeoutId);
-      }
-      maxTimeoutId = timeoutId = trailingCall = undefined;
-      if (trailing || (maxWait !== wait)) {
-        lastCalled = now();
-        result = func.apply(thisArg, args);
-        if (!timeoutId && !maxTimeoutId) {
-          args = thisArg = null;
-        }
-      }
+      complete(trailing, timeoutId);
     }
 
     function debounced() {
@@ -177,7 +172,7 @@ define(['../lang/isObject', '../date/now'], function(isObject, now) {
         result = func.apply(thisArg, args);
       }
       if (isCalled && !timeoutId && !maxTimeoutId) {
-        args = thisArg = null;
+        args = thisArg = undefined;
       }
       return result;
     }

function/defer.js

@@ -2,7 +2,7 @@ define(['../internal/baseDelay', './restParam'], function(baseDelay, restParam)
 
   /**
    * Defers invoking the `func` until the current call stack has cleared. Any
-   * additional arguments are provided to `func` when it is invoked.
+   * additional arguments are provided to `func` when it's invoked.
    *
    * @static
    * @memberOf _

function/delay.js

@@ -2,7 +2,7 @@ define(['../internal/baseDelay', './restParam'], function(baseDelay, restParam)
 
   /**
    * Invokes `func` after `wait` milliseconds. Any additional arguments are
-   * provided to `func` when it is invoked.
+   * provided to `func` when it's invoked.
    *
    * @static
    * @memberOf _

function/memoize.js

@@ -13,7 +13,7 @@ define(['../internal/MapCache'], function(MapCache) {
    *
    * **Note:** The cache is exposed as the `cache` property on the memoized
    * function. Its creation may be customized by replacing the `_.memoize.Cache`
-   * constructor with one whose instances implement the [`Map`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-properties-of-the-map-prototype-object)
+   * constructor with one whose instances implement the [`Map`](http://ecma-international.org/ecma-262/6.0/#sec-properties-of-the-map-prototype-object)
    * method interface of `get`, `has`, and `set`.
    *
    * @static
@@ -60,14 +60,14 @@ define(['../internal/MapCache'], function(MapCache) {
     }
     var memoized = function() {
       var args = arguments,
-          cache = memoized.cache,
-          key = resolver ? resolver.apply(this, args) : args[0];
+          key = resolver ? resolver.apply(this, args) : args[0],
+          cache = memoized.cache;
 
       if (cache.has(key)) {
         return cache.get(key);
       }
       var result = func.apply(this, args);
-      cache.set(key, result);
+      memoized.cache = cache.set(key, result);
       return result;
     };
     memoized.cache = new memoize.Cache;

function/modArgs.js

@@ -0,0 +1,56 @@
+define(['../internal/arrayEvery', '../internal/baseFlatten', '../internal/baseIsFunction', './restParam'], function(arrayEvery, baseFlatten, baseIsFunction, restParam) {
+
+  /** Used as the `TypeError` message for "Functions" methods. */
+  var FUNC_ERROR_TEXT = 'Expected a function';
+
+  /* Native method references for those with the same name as other `lodash` methods. */
+  var nativeMin = Math.min;
+
+  /**
+   * Creates a function that runs each argument through a corresponding
+   * transform function.
+   *
+   * @static
+   * @memberOf _
+   * @category Function
+   * @param {Function} func The function to wrap.
+   * @param {...(Function|Function[])} [transforms] The functions to transform
+   * arguments, specified as individual functions or arrays of functions.
+   * @returns {Function} Returns the new function.
+   * @example
+   *
+   * function doubled(n) {
+   *   return n * 2;
+   * }
+   *
+   * function square(n) {
+   *   return n * n;
+   * }
+   *
+   * var modded = _.modArgs(function(x, y) {
+   *   return [x, y];
+   * }, square, doubled);
+   *
+   * modded(1, 2);
+   * // => [1, 4]
+   *
+   * modded(5, 10);
+   * // => [25, 20]
+   */
+  var modArgs = restParam(function(func, transforms) {
+    transforms = baseFlatten(transforms);
+    if (typeof func != 'function' || !arrayEvery(transforms, baseIsFunction)) {
+      throw new TypeError(FUNC_ERROR_TEXT);
+    }
+    var length = transforms.length;
+    return restParam(function(args) {
+      var index = nativeMin(args.length, length);
+      while (index--) {
+        args[index] = transforms[index](args[index]);
+      }
+      return func.apply(this, args);
+    });
+  });
+
+  return modArgs;
+});

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/rearg.js

@@ -1,5 +1,8 @@
 define(['../internal/baseFlatten', '../internal/createWrapper', './restParam'], function(baseFlatten, createWrapper, restParam) {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /** Used to compose bitmasks for wrapper metadata. */
   var REARG_FLAG = 256;
 
@@ -32,7 +35,7 @@ define(['../internal/baseFlatten', '../internal/createWrapper', './restParam'],
    * // => [3, 6, 9]
    */
   var rearg = restParam(function(func, indexes) {
-    return createWrapper(func, REARG_FLAG, null, null, null, baseFlatten(indexes));
+    return createWrapper(func, REARG_FLAG, undefined, undefined, undefined, baseFlatten(indexes));
   });
 
   return rearg;

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';
 
@@ -10,7 +13,7 @@ define([], function() {
    * Creates a function that invokes `func` with the `this` binding of the
    * created function and arguments from `start` and beyond provided as an array.
    *
-   * **Note:** This method is based on the [rest parameter](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Functions/rest_parameters).
+   * **Note:** This method is based on the [rest parameter](https://developer.mozilla.org/Web/JavaScript/Reference/Functions/rest_parameters).
    *
    * @static
    * @memberOf _
@@ -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,

function/spread.js

@@ -7,7 +7,7 @@ define([], function() {
    * Creates a function that invokes `func` with the `this` binding of the created
    * function and an array of arguments much like [`Function#apply`](https://es5.github.io/#x15.3.4.3).
    *
-   * **Note:** This method is based on the [spread operator](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Spread_operator).
+   * **Note:** This method is based on the [spread operator](https://developer.mozilla.org/Web/JavaScript/Reference/Operators/Spread_operator).
    *
    * @static
    * @memberOf _

function/throttle.js

@@ -3,20 +3,13 @@ define(['./debounce', '../lang/isObject'], function(debounce, isObject) {
   /** Used as the `TypeError` message for "Functions" methods. */
   var FUNC_ERROR_TEXT = 'Expected a function';
 
-  /** Used as an internal `_.debounce` options object by `_.throttle`. */
-  var debounceOptions = {
-    'leading': false,
-    'maxWait': 0,
-    'trailing': false
-  };
-
   /**
-   * Creates a function that only invokes `func` at most once per every `wait`
-   * milliseconds. The created function comes with a `cancel` method to cancel
-   * delayed invocations. Provide an options object to indicate that `func`
-   * should be invoked on the leading and/or trailing edge of the `wait` timeout.
-   * Subsequent calls to the throttled function return the result of the last
-   * `func` call.
+   * Creates a throttled function that only invokes `func` at most once per
+   * every `wait` milliseconds. The throttled function comes with a `cancel`
+   * method to cancel delayed invocations. Provide an options object to indicate
+   * that `func` should be invoked on the leading and/or trailing edge of the
+   * `wait` timeout. Subsequent calls to the throttled function return the
+   * result of the last `func` call.
    *
    * **Note:** If `leading` and `trailing` options are `true`, `func` is invoked
    * on the trailing edge of the timeout only if the the throttled function is
@@ -62,10 +55,7 @@ define(['./debounce', '../lang/isObject'], function(debounce, isObject) {
       leading = 'leading' in options ? !!options.leading : leading;
       trailing = 'trailing' in options ? !!options.trailing : trailing;
     }
-    debounceOptions.leading = leading;
-    debounceOptions.maxWait = +wait;
-    debounceOptions.trailing = trailing;
-    return debounce(func, wait, debounceOptions);
+    return debounce(func, wait, { 'leading': leading, 'maxWait': +wait, 'trailing': trailing });
   }
 
   return throttle;

function/wrap.js

@@ -1,5 +1,8 @@
 define(['../internal/createWrapper', '../utility/identity'], function(createWrapper, identity) {
 
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
   /** Used to compose bitmasks for wrapper metadata. */
   var PARTIAL_FLAG = 32;
 
@@ -26,7 +29,7 @@ define(['../internal/createWrapper', '../utility/identity'], function(createWrap
    */
   function wrap(value, wrapper) {
     wrapper = wrapper == null ? identity : wrapper;
-    return createWrapper(wrapper, PARTIAL_FLAG, null, [value], []);
+    return createWrapper(wrapper, PARTIAL_FLAG, undefined, [value], []);
   }
 
   return wrap;

internal/LazyWrapper.js

@@ -11,13 +11,12 @@ define(['./baseCreate', './baseLodash'], function(baseCreate, baseLodash) {
    */
   function LazyWrapper(value) {
     this.__wrapped__ = value;
-    this.__actions__ = null;
+    this.__actions__ = [];
     this.__dir__ = 1;
-    this.__dropCount__ = 0;
     this.__filtered__ = false;
-    this.__iteratees__ = null;
+    this.__iteratees__ = [];
     this.__takeCount__ = POSITIVE_INFINITY;
-    this.__views__ = null;
+    this.__views__ = [];
   }
 
   LazyWrapper.prototype = baseCreate(baseLodash.prototype);

internal/SetCache.js

@@ -1,10 +1,10 @@
-define(['./cachePush', '../lang/isNative', './root'], function(cachePush, isNative, root) {
+define(['./cachePush', './getNative', './root'], function(cachePush, getNative, root) {
 
   /** Native method references. */
-  var Set = isNative(Set = root.Set) && Set;
+  var Set = getNative(root, 'Set');
 
   /* Native method references for those with the same name as other `lodash` methods. */
-  var nativeCreate = isNative(nativeCreate = Object.create) && nativeCreate;
+  var nativeCreate = getNative(Object, 'create');
 
   /**
    *

internal/arrayConcat.js

@@ -0,0 +1,28 @@
+define([], function() {
+
+  /**
+   * Creates a new array joining `array` with `other`.
+   *
+   * @private
+   * @param {Array} array The array to join.
+   * @param {Array} other The other array to join.
+   * @returns {Array} Returns the new concatenated array.
+   */
+  function arrayConcat(array, other) {
+    var index = -1,
+        length = array.length,
+        othIndex = -1,
+        othLength = other.length,
+        result = Array(length + othLength);
+
+    while (++index < length) {
+      result[index] = array[index];
+    }
+    while (++othIndex < othLength) {
+      result[index++] = other[othIndex];
+    }
+    return result;
+  }
+
+  return arrayConcat;
+});

internal/arrayExtremum.js

@@ -0,0 +1,33 @@
+define([], function() {
+
+  /**
+   * A specialized version of `baseExtremum` for arrays which invokes `iteratee`
+   * with one argument: (value).
+   *
+   * @private
+   * @param {Array} array The array to iterate over.
+   * @param {Function} iteratee The function invoked per iteration.
+   * @param {Function} comparator The function used to compare values.
+   * @param {*} exValue The initial extremum value.
+   * @returns {*} Returns the extremum value.
+   */
+  function arrayExtremum(array, iteratee, comparator, exValue) {
+    var index = -1,
+        length = array.length,
+        computed = exValue,
+        result = computed;
+
+    while (++index < length) {
+      var value = array[index],
+          current = +iteratee(value);
+
+      if (comparator(current, computed)) {
+        computed = current;
+        result = value;
+      }
+    }
+    return result;
+  }
+
+  return arrayExtremum;
+});

internal/arrayMax.js

@@ -1,28 +0,0 @@
-define([], function() {
-
-  /** Used as references for `-Infinity` and `Infinity`. */
-  var NEGATIVE_INFINITY = Number.NEGATIVE_INFINITY;
-
-  /**
-   * A specialized version of `_.max` for arrays without support for iteratees.
-   *
-   * @private
-   * @param {Array} array The array to iterate over.
-   * @returns {*} Returns the maximum value.
-   */
-  function arrayMax(array) {
-    var index = -1,
-        length = array.length,
-        result = NEGATIVE_INFINITY;
-
-    while (++index < length) {
-      var value = array[index];
-      if (value > result) {
-        result = value;
-      }
-    }
-    return result;
-  }
-
-  return arrayMax;
-});

internal/arrayMin.js

@@ -1,28 +0,0 @@
-define([], function() {
-
-  /** Used as references for `-Infinity` and `Infinity`. */
-  var POSITIVE_INFINITY = Number.POSITIVE_INFINITY;
-
-  /**
-   * A specialized version of `_.min` for arrays without support for iteratees.
-   *
-   * @private
-   * @param {Array} array The array to iterate over.
-   * @returns {*} Returns the minimum value.
-   */
-  function arrayMin(array) {
-    var index = -1,
-        length = array.length,
-        result = POSITIVE_INFINITY;
-
-    while (++index < length) {
-      var value = array[index];
-      if (value < result) {
-        result = value;
-      }
-    }
-    return result;
-  }
-
-  return arrayMin;
-});

internal/arrayPush.js

@@ -0,0 +1,23 @@
+define([], function() {
+
+  /**
+   * Appends the elements of `values` to `array`.
+   *
+   * @private
+   * @param {Array} array The array to modify.
+   * @param {Array} values The values to append.
+   * @returns {Array} Returns `array`.
+   */
+  function arrayPush(array, values) {
+    var index = -1,
+        length = values.length,
+        offset = array.length;
+
+    while (++index < length) {
+      array[offset + index] = values[index];
+    }
+    return array;
+  }
+
+  return arrayPush;
+});

internal/arraySum.js

@@ -1,18 +1,20 @@
 define([], function() {
 
   /**
-   * A specialized version of `_.sum` for arrays without support for iteratees.
+   * A specialized version of `_.sum` for arrays without support for callback
+   * shorthands and `this` binding..
    *
    * @private
    * @param {Array} array The array to iterate over.
+   * @param {Function} iteratee The function invoked per iteration.
    * @returns {number} Returns the sum.
    */
-  function arraySum(array) {
+  function arraySum(array, iteratee) {
     var length = array.length,
         result = 0;
 
     while (length--) {
-      result += +array[length] || 0;
+      result += +iteratee(array[length]) || 0;
     }
     return result;
   }

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 +1,36 @@
+define(['../object/keys'], function(keys) {
+
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
+
+  /**
+   * 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 index = -1,
+        props = keys(source),
+        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

@@ -2,33 +2,17 @@ define(['./baseCopy', '../object/keys'], function(baseCopy, keys) {
 
   /**
    * 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;
+  function baseAssign(object, source) {
+    return source == null
+      ? object
+      : baseCopy(source, keys(source), object);
   }
 
   return baseAssign;

internal/baseAt.js

@@ -1,31 +1,31 @@
-define(['./isIndex', './isLength'], function(isIndex, isLength) {
+define(['./isArrayLike', './isIndex'], function(isArrayLike, isIndex) {
 
   /** Used as a safe reference for `undefined` in pre-ES5 environments. */
   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) {
     var index = -1,
-        length = collection.length,
-        isArr = isLength(length),
+        isNil = collection == null,
+        isArr = !isNil && isArrayLike(collection),
+        length = isArr ? collection.length : 0,
         propsLength = props.length,
         result = Array(propsLength);
 
     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];
+        result[index] = isNil ? undefined : collection[key];
       }
     }
     return result;

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]',
@@ -45,7 +48,7 @@ define(['./arrayCopy', './arrayEach', './baseCopy', './baseForOwn', './initClone
   var objectProto = Object.prototype;
 
   /**
-   * Used to resolve the [`toStringTag`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.prototype.tostring)
+   * Used to resolve the [`toStringTag`](http://ecma-international.org/ecma-262/6.0/#sec-object.prototype.tostring)
    * of values.
    */
   var objToString = objectProto.toString;
@@ -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]
@@ -96,7 +99,7 @@ define(['./arrayCopy', './arrayEach', './baseCopy', './baseForOwn', './initClone
           : (object ? value : {});
       }
     }
-    // Check for circular references and return corresponding clone.
+    // Check for circular references and return its corresponding clone.
     stackA || (stackA = []);
     stackB || (stackB = []);
 

internal/baseCompareAscending.js

@@ -1,23 +1,35 @@
 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.
    *
    * @private
-   * @param {*} value The value to compare to `other`.
-   * @param {*} other The value to compare to `value`.
+   * @param {*} value The value to compare.
+   * @param {*} other The other value to compare.
    * @returns {number} Returns the sort order indicator for `value`.
    */
   function baseCompareAscending(value, other) {
     if (value !== other) {
-      var valIsReflexive = value === value,
+      var valIsNull = value === null,
+          valIsUndef = value === undefined,
+          valIsReflexive = value === value;
+
+      var othIsNull = other === null,
+          othIsUndef = other === undefined,
           othIsReflexive = other === other;
 
-      if (value > other || !valIsReflexive || (typeof value == 'undefined' && othIsReflexive)) {
+      if ((value > other && !othIsNull) || !valIsReflexive ||
+          (valIsNull && !othIsUndef && othIsReflexive) ||
+          (valIsUndef && othIsReflexive)) {
         return 1;
       }
-      if (value < other || !othIsReflexive || (typeof other == 'undefined' && valIsReflexive)) {
+      if ((value < other && !valIsNull) || !othIsReflexive ||
+          (othIsNull && !valIsUndef && valIsReflexive) ||
+          (othIsUndef && 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/baseCreate.js

@@ -1,4 +1,7 @@
-define(['../lang/isObject', './root'], function(isObject, root) {
+define(['../lang/isObject'], function(isObject) {
+
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
 
   /**
    * The base implementation of `_.create` without support for assigning
@@ -9,14 +12,14 @@ define(['../lang/isObject', './root'], function(isObject, root) {
    * @returns {Object} Returns the new object.
    */
   var baseCreate = (function() {
-    function Object() {}
+    function object() {}
     return function(prototype) {
       if (isObject(prototype)) {
-        Object.prototype = prototype;
-        var result = new Object;
-        Object.prototype = null;
+        object.prototype = prototype;
+        var result = new object;
+        object.prototype = undefined;
       }
-      return result || root.Object();
+      return result || {};
     };
   }());
 

internal/baseDifference.js

@@ -1,5 +1,8 @@
 define(['./baseIndexOf', './cacheIndexOf', './createCache'], function(baseIndexOf, cacheIndexOf, createCache) {
 
+  /** Used as the size to enable large array optimizations. */
+  var LARGE_ARRAY_SIZE = 200;
+
   /**
    * The base implementation of `_.difference` which accepts a single array
    * of values to exclude.
@@ -19,7 +22,7 @@ define(['./baseIndexOf', './cacheIndexOf', './createCache'], function(baseIndexO
     var index = -1,
         indexOf = baseIndexOf,
         isCommon = true,
-        cache = (isCommon && values.length >= 200) ? createCache(values) : null,
+        cache = (isCommon && values.length >= LARGE_ARRAY_SIZE) ? createCache(values) : null,
         valuesLength = values.length;
 
     if (cache) {

internal/baseExtremum.js

@@ -1,30 +1,24 @@
 define(['./baseEach'], function(baseEach) {
 
-  /** Used as references for `-Infinity` and `Infinity`. */
-  var NEGATIVE_INFINITY = Number.NEGATIVE_INFINITY,
-      POSITIVE_INFINITY = Number.POSITIVE_INFINITY;
-
   /**
    * Gets the extremum value of `collection` invoking `iteratee` for each value
    * in `collection` to generate the criterion by which the value is ranked.
-   * The `iteratee` is invoked with three arguments: (value, index, collection).
+   * The `iteratee` is invoked with three arguments: (value, index|key, collection).
    *
    * @private
    * @param {Array|Object|string} collection The collection to iterate over.
    * @param {Function} iteratee The function invoked per iteration.
-   * @param {boolean} [isMin] Specify returning the minimum, instead of the
-   *  maximum, extremum value.
+   * @param {Function} comparator The function used to compare values.
+   * @param {*} exValue The initial extremum value.
    * @returns {*} Returns the extremum value.
    */
-  function extremumBy(collection, iteratee, isMin) {
-    var exValue = isMin ? POSITIVE_INFINITY : NEGATIVE_INFINITY,
-        computed = exValue,
+  function baseExtremum(collection, iteratee, comparator, exValue) {
+    var computed = exValue,
         result = computed;
 
     baseEach(collection, function(value, index, collection) {
-      var current = iteratee(value, index, collection);
-      if ((isMin ? (current < computed) : (current > computed)) ||
-          (current === exValue && current === result)) {
+      var current = +iteratee(value, index, collection);
+      if (comparator(current, computed) || (current === exValue && current === result)) {
         computed = current;
         result = value;
       }
@@ -32,5 +26,5 @@ define(['./baseEach'], function(baseEach) {
     return result;
   }
 
-  return extremumBy;
+  return baseExtremum;
 });

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/baseFlatten.js

@@ -1,4 +1,4 @@
-define(['../lang/isArguments', '../lang/isArray', './isLength', './isObjectLike'], function(isArguments, isArray, isLength, isObjectLike) {
+define(['./arrayPush', '../lang/isArguments', '../lang/isArray', './isArrayLike', './isObjectLike'], function(arrayPush, isArguments, isArray, isArrayLike, isObjectLike) {
 
   /**
    * The base implementation of `_.flatten` with added support for restricting
@@ -6,33 +6,29 @@ define(['../lang/isArguments', '../lang/isArray', './isLength', './isObjectLike'
    *
    * @private
    * @param {Array} array The array to flatten.
-   * @param {boolean} isDeep Specify a deep flatten.
-   * @param {boolean} isStrict Restrict flattening to arrays and `arguments` objects.
+   * @param {boolean} [isDeep] Specify a deep flatten.
+   * @param {boolean} [isStrict] Restrict flattening to arrays-like objects.
+   * @param {Array} [result=[]] The initial result value.
    * @returns {Array} Returns the new flattened array.
    */
-  function baseFlatten(array, isDeep, isStrict) {
+  function baseFlatten(array, isDeep, isStrict, result) {
+    result || (result = []);
+
     var index = -1,
-        length = array.length,
-        resIndex = -1,
-        result = [];
+        length = array.length;
 
     while (++index < length) {
       var value = array[index];
-
-      if (isObjectLike(value) && isLength(value.length) && (isArray(value) || isArguments(value))) {
+      if (isObjectLike(value) && isArrayLike(value) &&
+          (isStrict || isArray(value) || isArguments(value))) {
         if (isDeep) {
           // Recursively flatten arrays (susceptible to call stack limits).
-          value = baseFlatten(value, isDeep, isStrict);
-        }
-        var valIndex = -1,
-            valLength = value.length;
-
-        result.length += valLength;
-        while (++valIndex < valLength) {
-          result[++resIndex] = value[valIndex];
+          baseFlatten(value, isDeep, isStrict, result);
+        } else {
+          arrayPush(result, value);
         }
       } else if (!isStrict) {
-        result[++resIndex] = value;
+        result[result.length] = value;
       }
     }
     return result;

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 = 0,
+        length = path.length;
+
+    while (object != null && index < length) {
+      object = object[path[index++]];
+    }
+    return (index && index == length) ? object : undefined;
+  }
+
+  return baseGet;
+});

internal/baseIsEqual.js

@@ -1,4 +1,4 @@
-define(['./baseIsEqualDeep'], function(baseIsEqualDeep) {
+define(['./baseIsEqualDeep', '../lang/isObject', './isObjectLike'], function(baseIsEqualDeep, isObject, isObjectLike) {
 
   /**
    * The base implementation of `_.isEqual` without support for `this` binding
@@ -14,18 +14,10 @@ define(['./baseIsEqualDeep'], function(baseIsEqualDeep) {
    * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
    */
   function baseIsEqual(value, other, customizer, isLoose, stackA, stackB) {
-    // Exit early for identical values.
     if (value === other) {
-      // Treat `+0` vs. `-0` as not equal.
-      return value !== 0 || (1 / value == 1 / other);
+      return true;
     }
-    var valType = typeof value,
-        othType = typeof other;
-
-    // Exit early for unlike primitive values.
-    if ((valType != 'function' && valType != 'object' && othType != 'function' && othType != 'object') ||
-        value == null || other == null) {
-      // Return `false` unless both values are `NaN`.
+    if (value == null || other == null || (!isObject(value) && !isObjectLike(other))) {
       return value !== value && other !== other;
     }
     return baseIsEqualDeep(value, other, baseIsEqual, customizer, isLoose, stackA, stackB);

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. */
@@ -13,7 +12,7 @@ define(['./equalArrays', './equalByTag', './equalObjects', '../lang/isArray', '.
   var hasOwnProperty = objectProto.hasOwnProperty;
 
   /**
-   * Used to resolve the [`toStringTag`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.prototype.tostring)
+   * Used to resolve the [`toStringTag`](http://ecma-international.org/ecma-262/6.0/#sec-object.prototype.tostring)
    * of values.
    */
   var objToString = objectProto.toString;
@@ -55,28 +54,24 @@ 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 {
-      var valWrapped = objIsObj && hasOwnProperty.call(object, '__wrapped__'),
-          othWrapped = othIsObj && hasOwnProperty.call(other, '__wrapped__');
+    if (!isLoose) {
+      var objIsWrapped = objIsObj && hasOwnProperty.call(object, '__wrapped__'),
+          othIsWrapped = 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 (objIsWrapped || othIsWrapped) {
+        return equalFunc(objIsWrapped ? object.value() : object, othIsWrapped ? other.value() : other, customizer, isLoose, stackA, stackB);
       }
     }
+    if (!isSameTag) {
+      return false;
+    }
     // Assume cyclic values are equal.
     // For more information on detecting circular references see https://es5.github.io/#JO.
     stackA || (stackA = []);

internal/baseIsMatch.js

@@ -1,4 +1,4 @@
-define(['./baseIsEqual'], function(baseIsEqual) {
+define(['./baseIsEqual', './toObject'], function(baseIsEqual, toObject) {
 
   /** Used as a safe reference for `undefined` in pre-ES5 environments. */
   var undefined;
@@ -9,41 +9,43 @@ define(['./baseIsEqual'], function(baseIsEqual) {
    *
    * @private
    * @param {Object} object The object to inspect.
-   * @param {Array} props The source property names to match.
-   * @param {Array} values The source values to match.
-   * @param {Array} strictCompareFlags Strict comparison flags for source values.
+   * @param {Array} matchData The propery names, values, and compare flags to match.
    * @param {Function} [customizer] The function to customize comparing objects.
    * @returns {boolean} Returns `true` if `object` is a match, else `false`.
    */
-  function baseIsMatch(object, props, values, strictCompareFlags, customizer) {
-    var index = -1,
-        length = props.length,
+  function baseIsMatch(object, matchData, customizer) {
+    var index = matchData.length,
+        length = index,
         noCustomizer = !customizer;
 
-    while (++index < length) {
-      if ((noCustomizer && strictCompareFlags[index])
-            ? values[index] !== object[props[index]]
-            : !(props[index] in object)
+    if (object == null) {
+      return !length;
+    }
+    object = toObject(object);
+    while (index--) {
+      var data = matchData[index];
+      if ((noCustomizer && data[2])
+            ? data[1] !== object[data[0]]
+            : !(data[0] in object)
           ) {
         return false;
       }
     }
-    index = -1;
     while (++index < length) {
-      var key = props[index],
+      data = matchData[index];
+      var key = data[0],
           objValue = object[key],
-          srcValue = values[index];
+          srcValue = data[1];
 
-      if (noCustomizer && strictCompareFlags[index]) {
-        var result = typeof objValue != 'undefined' || (key in object);
-      } else {
-        result = customizer ? customizer(objValue, srcValue, key) : undefined;
-        if (typeof result == 'undefined') {
-          result = baseIsEqual(srcValue, objValue, customizer, true);
+      if (noCustomizer && data[2]) {
+        if (objValue === undefined && !(key in object)) {
+          return false;
+        }
+      } else {
+        var result = customizer ? customizer(objValue, srcValue, key) : undefined;
+        if (!(result === undefined ? baseIsEqual(srcValue, objValue, customizer, true) : result)) {
+          return false;
         }
-      }
-      if (!result) {
-        return false;
       }
     }
     return true;

internal/baseMap.js

@@ -1,4 +1,4 @@
-define(['./baseEach'], function(baseEach) {
+define(['./baseEach', './isArrayLike'], function(baseEach, isArrayLike) {
 
   /**
    * The base implementation of `_.map` without support for callback shorthands
@@ -10,9 +10,11 @@ define(['./baseEach'], function(baseEach) {
    * @returns {Array} Returns the new mapped array.
    */
   function baseMap(collection, iteratee) {
-    var result = [];
+    var index = -1,
+        result = isArrayLike(collection) ? Array(collection.length) : [];
+
     baseEach(collection, function(value, key, collection) {
-      result.push(iteratee(value, key, collection));
+      result[++index] = iteratee(value, key, collection);
     });
     return result;
   }

internal/baseMatches.js

@@ -1,4 +1,7 @@
-define(['./baseIsMatch', '../utility/constant', './isStrictComparable', '../object/keys', './toObject'], function(baseIsMatch, constant, isStrictComparable, keys, toObject) {
+define(['./baseIsMatch', './getMatchData', './toObject'], function(baseIsMatch, getMatchData, toObject) {
+
+  /** Used as a safe reference for `undefined` in pre-ES5 environments. */
+  var undefined;
 
   /**
    * The base implementation of `_.matches` which does not clone `source`.
@@ -8,33 +11,20 @@ define(['./baseIsMatch', '../utility/constant', './isStrictComparable', '../obje
    * @returns {Function} Returns the new function.
    */
   function baseMatches(source) {
-    var props = keys(source),
-        length = props.length;
+    var matchData = getMatchData(source);
+    if (matchData.length == 1 && matchData[0][2]) {
+      var key = matchData[0][0],
+          value = matchData[0][1];
 
-    if (!length) {
-      return constant(true);
-    }
-    if (length == 1) {
-      var key = props[0],
-          value = source[key];
-
-      if (isStrictComparable(value)) {
-        return function(object) {
-          return object != null && object[key] === value &&
-            (typeof value != 'undefined' || (key in toObject(object)));
-        };
-      }
-    }
-    var values = Array(length),
-        strictCompareFlags = Array(length);
-
-    while (length--) {
-      value = source[props[length]];
-      values[length] = value;
-      strictCompareFlags[length] = isStrictComparable(value);
+      return function(object) {
+        if (object == null) {
+          return false;
+        }
+        return object[key] === value && (value !== undefined || (key in toObject(object)));
+      };
     }
     return function(object) {
-      return object != null && baseIsMatch(toObject(object), props, values, strictCompareFlags);
+      return baseIsMatch(object, matchData);
     };
   }
 

internal/baseMatchesProperty.js

@@ -1,23 +1,39 @@
-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 clone `srcValue`.
    *
    * @private
-   * @param {string} key The key of the property to get.
-   * @param {*} value The value to compare.
+   * @param {string} path The path of the property to get.
+   * @param {*} srcValue 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, srcValue) {
+    var isArr = isArray(path),
+        isCommon = isKey(path) && isStrictComparable(srcValue),
+        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] === srcValue
+        ? (srcValue !== undefined || (key in object))
+        : baseIsEqual(srcValue, object[key], undefined, true);
     };
   }
 

internal/baseMerge.js

@@ -1,4 +1,4 @@
-define(['./arrayEach', './baseForOwn', './baseMergeDeep', '../lang/isArray', './isLength', '../lang/isObject', './isObjectLike', '../lang/isTypedArray'], function(arrayEach, baseForOwn, baseMergeDeep, isArray, isLength, isObject, isObjectLike, isTypedArray) {
+define(['./arrayEach', './baseMergeDeep', '../lang/isArray', './isArrayLike', '../lang/isObject', './isObjectLike', '../lang/isTypedArray', '../object/keys'], function(arrayEach, baseMergeDeep, isArray, isArrayLike, isObject, isObjectLike, isTypedArray, keys) {
 
   /** Used as a safe reference for `undefined` in pre-ES5 environments. */
   var undefined;
@@ -10,32 +10,40 @@ define(['./arrayEach', './baseForOwn', './baseMergeDeep', '../lang/isArray', './
    * @private
    * @param {Object} object The destination object.
    * @param {Object} source The source object.
-   * @param {Function} [customizer] The function to customize merging properties.
+   * @param {Function} [customizer] The function to customize merged values.
    * @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) {
+    var isSrcArr = isArrayLike(source) && (isArray(source) || isTypedArray(source)),
+        props = isSrcArr ? undefined : keys(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 ((result !== undefined || (isSrcArr && !(key in object))) &&
+            (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', '../lang/isArguments', '../lang/isArray', './isArrayLike', '../lang/isPlainObject', '../lang/isTypedArray', '../lang/toPlainObject'], function(arrayCopy, isArguments, isArray, isArrayLike, isPlainObject, isTypedArray, toPlainObject) {
 
   /** Used as a safe reference for `undefined` in pre-ES5 environments. */
   var undefined;
@@ -13,7 +13,7 @@ define(['./arrayCopy', '../lang/isArguments', '../lang/isArray', './isLength', '
    * @param {Object} source The source object.
    * @param {string} key The key of the value to merge.
    * @param {Function} mergeFunc The function to merge values.
-   * @param {Function} [customizer] The function to customize merging properties.
+   * @param {Function} [customizer] The function to customize merged values.
    * @param {Array} [stackA=[]] Tracks traversed source objects.
    * @param {Array} [stackB=[]] Associates values with source counterparts.
    * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
@@ -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))) {
+      if (isArrayLike(srcValue) && (isArray(srcValue) || isTypedArray(srcValue))) {
         result = isArray(value)
           ? value
-          : ((value && value.length) ? arrayCopy(value) : []);
+          : (isArrayLike(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.