Bump to v4.2.1.

README.md

@@ -1,34 +1,34 @@
-# lodash v4.0.0
+# lodash v4.2.1
 
 The [lodash](https://lodash.com/) library exported as [Node.js](https://nodejs.org/) modules.
 
-Generated using [lodash-cli](https://www.npmjs.com/package/lodash-cli):
-```bash
-$ lodash modularize exports=node -o ./
-$ lodash -d -o ./lodash.js
-```
-
 ## Installation
 
 Using npm:
-
 ```bash
 $ {sudo -H} npm i -g npm
 $ npm i --save lodash
 ```
 
 In Node.js:
-
 ```js
-// load the modern build
+// load the full build
 var _ = require('lodash');
+// load the core build
+var _ = require('lodash/core');
+// load the fp build for immutable auto-curried iteratee-first data-last methods
+var _ = require('lodash/fp');
+
 // or a method category
 var array = require('lodash/array');
-// or a method (great for smaller builds with browserify/webpack)
+var object = require('lodash/fp/object');
+
+// or method for smaller builds with browserify/rollup/webpack
 var chunk = require('lodash/chunk');
+var extend = require('lodash/fp/extend');
 ```
 
-See the [package source](https://github.com/lodash/lodash/tree/4.0.0-npm) for more details.
+See the [package source](https://github.com/lodash/lodash/tree/4.2.1-npm) for more details.
 
 **Note:**<br>
 Don’t assign values to the [special variable](http://nodejs.org/api/repl.html#repl_repl_features) `_` when in the REPL.<br>
@@ -36,11 +36,11 @@ Install [n_](https://www.npmjs.com/package/n_) for a REPL that includes lodash b
 
 ## Module formats
 
-lodash is also available in a variety of other builds & module formats.
+Lodash is available in a variety of other builds & module formats.
 
- * [lodash](https://www.npmjs.com/package/lodash) & [per method](https://www.npmjs.com/browse/keyword/lodash-modularized) packages
+ * [lodash](https://www.npmjs.com/package/lodash) & [per method packages](https://www.npmjs.com/browse/keyword/lodash-modularized)
  * [lodash-amd](https://www.npmjs.com/package/lodash-amd)
- * [lodash-es](https://www.npmjs.com/package/lodash-es)
+ * [lodash-es](https://www.npmjs.com/package/lodash-es) & [babel-plugin-lodash](https://www.npmjs.com/package/babel-plugin-lodash)
 
 ## Further Reading
 
@@ -52,5 +52,5 @@ lodash is also available in a variety of other builds & module formats.
 
 ## Support
 
-Tested in Chrome 46-47, Firefox 42-43, IE 9-11, Edge 13, Safari 8-9, Node.js 0.10.x, 0.12.x, 4.x, & 5.x, &amp; PhantomJS 1.9.8.
+Tested in Chrome 47-48, Firefox 43-44, IE 9-11, Edge 13, Safari 8-9, Node.js 0.10, 0.12, 4, & 5, & PhantomJS 1.9.8.
 Automated [browser](https://saucelabs.com/u/lodash) & [CI](https://travis-ci.org/lodash/lodash/) test runs are available. Special thanks to [Sauce Labs](https://saucelabs.com/) for providing automated browser testing.

_Hash.js

@@ -1,7 +1,7 @@
-var nativeCreate = require('./nativeCreate');
+var nativeCreate = require('./_nativeCreate');
 
 /** Used for built-in method references. */
-var objectProto = global.Object.prototype;
+var objectProto = Object.prototype;
 
 /**
  * Creates an hash object.

_LazyWrapper.js

@@ -1,5 +1,5 @@
-var baseCreate = require('./baseCreate'),
-    baseLodash = require('./baseLodash');
+var baseCreate = require('./_baseCreate'),
+    baseLodash = require('./_baseLodash');
 
 /** Used as references for the maximum length and index of an array. */
 var MAX_ARRAY_LENGTH = 4294967295;

_LodashWrapper.js

@@ -1,5 +1,5 @@
-var baseCreate = require('./baseCreate'),
-    baseLodash = require('./baseLodash');
+var baseCreate = require('./_baseCreate'),
+    baseLodash = require('./_baseLodash');
 
 /**
  * The base constructor for creating `lodash` wrapper objects.

_Map.js

@@ -0,0 +1,7 @@
+var getNative = require('./_getNative'),
+    root = require('./_root');
+
+/* Built-in method references that are verified to be native. */
+var Map = getNative(root, 'Map');
+
+module.exports = Map;

_MapCache.js

@@ -1,8 +1,8 @@
-var mapClear = require('./mapClear'),
-    mapDelete = require('./mapDelete'),
-    mapGet = require('./mapGet'),
-    mapHas = require('./mapHas'),
-    mapSet = require('./mapSet');
+var mapClear = require('./_mapClear'),
+    mapDelete = require('./_mapDelete'),
+    mapGet = require('./_mapGet'),
+    mapHas = require('./_mapHas'),
+    mapSet = require('./_mapSet');
 
 /**
  * Creates a map cache object to store key-value pairs.

_Reflect.js

@@ -1,4 +1,6 @@
+var root = require('./_root');
+
 /** Built-in value references. */
-var Reflect = global.Reflect;
+var Reflect = root.Reflect;
 
 module.exports = Reflect;

_Set.js

@@ -0,0 +1,7 @@
+var getNative = require('./_getNative'),
+    root = require('./_root');
+
+/* Built-in method references that are verified to be native. */
+var Set = getNative(root, 'Set');
+
+module.exports = Set;

_SetCache.js

@@ -1,5 +1,5 @@
-var MapCache = require('./MapCache'),
-    cachePush = require('./cachePush');
+var MapCache = require('./_MapCache'),
+    cachePush = require('./_cachePush');
 
 /**
  *

_Stack.js

@@ -1,8 +1,8 @@
-var stackClear = require('./stackClear'),
-    stackDelete = require('./stackDelete'),
-    stackGet = require('./stackGet'),
-    stackHas = require('./stackHas'),
-    stackSet = require('./stackSet');
+var stackClear = require('./_stackClear'),
+    stackDelete = require('./_stackDelete'),
+    stackGet = require('./_stackGet'),
+    stackHas = require('./_stackHas'),
+    stackSet = require('./_stackSet');
 
 /**
  * Creates a stack cache object to store key-value pairs.

_Symbol.js

@@ -0,0 +1,6 @@
+var root = require('./_root');
+
+/** Built-in value references. */
+var Symbol = root.Symbol;
+
+module.exports = Symbol;

_Uint8Array.js

@@ -0,0 +1,6 @@
+var root = require('./_root');
+
+/** Built-in value references. */
+var Uint8Array = root.Uint8Array;
+
+module.exports = Uint8Array;

_WeakMap.js

@@ -0,0 +1,7 @@
+var getNative = require('./_getNative'),
+    root = require('./_root');
+
+/* Built-in method references that are verified to be native. */
+var WeakMap = getNative(root, 'WeakMap');
+
+module.exports = WeakMap;

_apply.js

@@ -5,11 +5,11 @@
  * @private
  * @param {Function} func The function to invoke.
  * @param {*} thisArg The `this` binding of `func`.
- * @param {...*} [args] The arguments to invoke `func` with.
+ * @param {...*} args The arguments to invoke `func` with.
  * @returns {*} Returns the result of `func`.
  */
 function apply(func, thisArg, args) {
-  var length = args ? args.length : 0;
+  var length = args.length;
   switch (length) {
     case 0: return func.call(thisArg);
     case 1: return func.call(thisArg, args[0]);

_arrayAggregator.js

@@ -0,0 +1,22 @@
+/**
+ * A specialized version of `baseAggregator` for arrays.
+ *
+ * @private
+ * @param {Array} array The array to iterate over.
+ * @param {Function} setter The function to set `accumulator` values.
+ * @param {Function} iteratee The iteratee to transform keys.
+ * @param {Object} accumulator The initial aggregated object.
+ * @returns {Function} Returns `accumulator`.
+ */
+function arrayAggregator(array, setter, iteratee, accumulator) {
+  var index = -1,
+      length = array.length;
+
+  while (++index < length) {
+    var value = array[index];
+    setter(accumulator, value, iteratee(value), array);
+  }
+  return accumulator;
+}
+
+module.exports = arrayAggregator;

_arrayIncludes.js

@@ -1,4 +1,4 @@
-var baseIndexOf = require('./baseIndexOf');
+var baseIndexOf = require('./_baseIndexOf');
 
 /**
  * A specialized version of `_.includes` for arrays without support for

_arrayReduce.js

@@ -6,14 +6,14 @@
  * @param {Array} array The array to iterate over.
  * @param {Function} iteratee The function invoked per iteration.
  * @param {*} [accumulator] The initial value.
- * @param {boolean} [initFromArray] Specify using the first element of `array` as the initial value.
+ * @param {boolean} [initAccum] Specify using the first element of `array` as the initial value.
  * @returns {*} Returns the accumulated value.
  */
-function arrayReduce(array, iteratee, accumulator, initFromArray) {
+function arrayReduce(array, iteratee, accumulator, initAccum) {
   var index = -1,
       length = array.length;
 
-  if (initFromArray && length) {
+  if (initAccum && length) {
     accumulator = array[++index];
   }
   while (++index < length) {

_arrayReduceRight.js

@@ -6,12 +6,12 @@
  * @param {Array} array The array to iterate over.
  * @param {Function} iteratee The function invoked per iteration.
  * @param {*} [accumulator] The initial value.
- * @param {boolean} [initFromArray] Specify using the last element of `array` as the initial value.
+ * @param {boolean} [initAccum] Specify using the last element of `array` as the initial value.
  * @returns {*} Returns the accumulated value.
  */
-function arrayReduceRight(array, iteratee, accumulator, initFromArray) {
+function arrayReduceRight(array, iteratee, accumulator, initAccum) {
   var length = array.length;
-  if (initFromArray && length) {
+  if (initAccum && length) {
     accumulator = array[--length];
   }
   while (length--) {

_assignInDefaults.js

@@ -1,7 +1,7 @@
-var eq = require('../eq');
+var eq = require('./eq');
 
 /** Used for built-in method references. */
-var objectProto = global.Object.prototype;
+var objectProto = Object.prototype;
 
 /** Used to check objects for own properties. */
 var hasOwnProperty = objectProto.hasOwnProperty;

_assignMergeValue.js

@@ -1,4 +1,4 @@
-var eq = require('../eq');
+var eq = require('./eq');
 
 /**
  * This function is like `assignValue` except that it doesn't assign `undefined` values.

_assignValue.js

@@ -1,7 +1,7 @@
-var eq = require('../eq');
+var eq = require('./eq');
 
 /** Used for built-in method references. */
-var objectProto = global.Object.prototype;
+var objectProto = Object.prototype;
 
 /** Used to check objects for own properties. */
 var hasOwnProperty = objectProto.hasOwnProperty;

_assocDelete.js

@@ -1,7 +1,7 @@
-var assocIndexOf = require('./assocIndexOf');
+var assocIndexOf = require('./_assocIndexOf');
 
 /** Used for built-in method references. */
-var arrayProto = global.Array.prototype;
+var arrayProto = Array.prototype;
 
 /** Built-in value references. */
 var splice = arrayProto.splice;

_assocGet.js

@@ -1,4 +1,4 @@
-var assocIndexOf = require('./assocIndexOf');
+var assocIndexOf = require('./_assocIndexOf');
 
 /**
  * Gets the associative array value for `key`.

_assocHas.js

@@ -1,4 +1,4 @@
-var assocIndexOf = require('./assocIndexOf');
+var assocIndexOf = require('./_assocIndexOf');
 
 /**
  * Checks if an associative array value for `key` exists.

_assocIndexOf.js

@@ -1,4 +1,4 @@
-var eq = require('../eq');
+var eq = require('./eq');
 
 /**
  * Gets the index at which the first occurrence of `key` is found in `array`

_assocSet.js

@@ -1,4 +1,4 @@
-var assocIndexOf = require('./assocIndexOf');
+var assocIndexOf = require('./_assocIndexOf');
 
 /**
  * Sets the associative array `key` to `value`.

_baseAggregator.js

@@ -0,0 +1,21 @@
+var baseEach = require('./_baseEach');
+
+/**
+ * Aggregates elements of `collection` on `accumulator` with keys transformed
+ * by `iteratee` and values set by `setter`.
+ *
+ * @private
+ * @param {Array|Object} collection The collection to iterate over.
+ * @param {Function} setter The function to set `accumulator` values.
+ * @param {Function} iteratee The iteratee to transform keys.
+ * @param {Object} accumulator The initial aggregated object.
+ * @returns {Function} Returns `accumulator`.
+ */
+function baseAggregator(collection, setter, iteratee, accumulator) {
+  baseEach(collection, function(value, key, collection) {
+    setter(accumulator, value, iteratee(value), collection);
+  });
+  return accumulator;
+}
+
+module.exports = baseAggregator;

_baseAssign.js

@@ -1,5 +1,5 @@
-var copyObject = require('./copyObject'),
-    keys = require('../keys');
+var copyObject = require('./_copyObject'),
+    keys = require('./keys');
 
 /**
  * The base implementation of `_.assign` without support for multiple sources

_baseAt.js

@@ -1,4 +1,4 @@
-var get = require('../get');
+var get = require('./get');
 
 /**
  * The base implementation of `_.at` without support for individual paths.

_baseClone.js

@@ -1,17 +1,17 @@
-var Stack = require('./Stack'),
-    arrayEach = require('./arrayEach'),
-    assignValue = require('./assignValue'),
-    baseAssign = require('./baseAssign'),
-    baseForOwn = require('./baseForOwn'),
-    copyArray = require('./copyArray'),
-    copySymbols = require('./copySymbols'),
-    getTag = require('./getTag'),
-    initCloneArray = require('./initCloneArray'),
-    initCloneByTag = require('./initCloneByTag'),
-    initCloneObject = require('./initCloneObject'),
-    isArray = require('../isArray'),
-    isHostObject = require('./isHostObject'),
-    isObject = require('../isObject');
+var Stack = require('./_Stack'),
+    arrayEach = require('./_arrayEach'),
+    assignValue = require('./_assignValue'),
+    baseAssign = require('./_baseAssign'),
+    baseForOwn = require('./_baseForOwn'),
+    copyArray = require('./_copyArray'),
+    copySymbols = require('./_copySymbols'),
+    getTag = require('./_getTag'),
+    initCloneArray = require('./_initCloneArray'),
+    initCloneByTag = require('./_initCloneByTag'),
+    initCloneObject = require('./_initCloneObject'),
+    isArray = require('./isArray'),
+    isHostObject = require('./_isHostObject'),
+    isObject = require('./isObject');
 
 /** `Object#toString` result references. */
 var argsTag = '[object Arguments]',

_baseConforms.js

@@ -1,4 +1,4 @@
-var keys = require('../keys');
+var keys = require('./keys');
 
 /**
  * The base implementation of `_.conforms` which doesn't clone `source`.

_baseCreate.js

@@ -1,4 +1,4 @@
-var isObject = require('../isObject');
+var isObject = require('./isObject');
 
 /**
  * The base implementation of `_.create` without support for assigning

_baseDifference.js

@@ -1,9 +1,9 @@
-var SetCache = require('./SetCache'),
-    arrayIncludes = require('./arrayIncludes'),
-    arrayIncludesWith = require('./arrayIncludesWith'),
-    arrayMap = require('./arrayMap'),
-    baseUnary = require('./baseUnary'),
-    cacheHas = require('./cacheHas');
+var SetCache = require('./_SetCache'),
+    arrayIncludes = require('./_arrayIncludes'),
+    arrayIncludesWith = require('./_arrayIncludesWith'),
+    arrayMap = require('./_arrayMap'),
+    baseUnary = require('./_baseUnary'),
+    cacheHas = require('./_cacheHas');
 
 /** Used as the size to enable large array optimizations. */
 var LARGE_ARRAY_SIZE = 200;

_baseEach.js

@@ -1,5 +1,5 @@
-var baseForOwn = require('./baseForOwn'),
-    createBaseEach = require('./createBaseEach');
+var baseForOwn = require('./_baseForOwn'),
+    createBaseEach = require('./_createBaseEach');
 
 /**
  * The base implementation of `_.forEach` without support for iteratee shorthands.

_baseEachRight.js

@@ -1,5 +1,5 @@
-var baseForOwnRight = require('./baseForOwnRight'),
-    createBaseEach = require('./createBaseEach');
+var baseForOwnRight = require('./_baseForOwnRight'),
+    createBaseEach = require('./_createBaseEach');
 
 /**
  * The base implementation of `_.forEachRight` without support for iteratee shorthands.

_baseEvery.js

@@ -1,4 +1,4 @@
-var baseEach = require('./baseEach');
+var baseEach = require('./_baseEach');
 
 /**
  * The base implementation of `_.every` without support for iteratee shorthands.

_baseFill.js

@@ -1,5 +1,5 @@
-var toInteger = require('../toInteger'),
-    toLength = require('../toLength');
+var toInteger = require('./toInteger'),
+    toLength = require('./toLength');
 
 /**
  * The base implementation of `_.fill` without an iteratee call guard.

_baseFilter.js

@@ -1,4 +1,4 @@
-var baseEach = require('./baseEach');
+var baseEach = require('./_baseEach');
 
 /**
  * The base implementation of `_.filter` without support for iteratee shorthands.

_baseFind.js

@@ -1,7 +1,7 @@
 /**
  * The base implementation of methods like `_.find` and `_.findKey`, without
  * support for iteratee shorthands, which iterates over `collection` using
- * the provided `eachFunc`.
+ * `eachFunc`.
  *
  * @private
  * @param {Array|Object} collection The collection to search.

_baseFlatten.js

@@ -1,7 +1,7 @@
-var arrayPush = require('./arrayPush'),
-    isArguments = require('../isArguments'),
-    isArray = require('../isArray'),
-    isArrayLikeObject = require('../isArrayLikeObject');
+var arrayPush = require('./_arrayPush'),
+    isArguments = require('./isArguments'),
+    isArray = require('./isArray'),
+    isArrayLikeObject = require('./isArrayLikeObject');
 
 /**
  * The base implementation of `_.flatten` with support for restricting flattening.

_baseFor.js

@@ -1,4 +1,4 @@
-var createBaseFor = require('./createBaseFor');
+var createBaseFor = require('./_createBaseFor');
 
 /**
  * The base implementation of `baseForIn` and `baseForOwn` which iterates

_baseForIn.js

@@ -1,5 +1,5 @@
-var baseFor = require('./baseFor'),
-    keysIn = require('../keysIn');
+var baseFor = require('./_baseFor'),
+    keysIn = require('./keysIn');
 
 /**
  * The base implementation of `_.forIn` without support for iteratee shorthands.

_baseForOwn.js

@@ -1,5 +1,5 @@
-var baseFor = require('./baseFor'),
-    keys = require('../keys');
+var baseFor = require('./_baseFor'),
+    keys = require('./keys');
 
 /**
  * The base implementation of `_.forOwn` without support for iteratee shorthands.

_baseForOwnRight.js

@@ -1,5 +1,5 @@
-var baseForRight = require('./baseForRight'),
-    keys = require('../keys');
+var baseForRight = require('./_baseForRight'),
+    keys = require('./keys');
 
 /**
  * The base implementation of `_.forOwnRight` without support for iteratee shorthands.

_baseForRight.js

@@ -1,4 +1,4 @@
-var createBaseFor = require('./createBaseFor');
+var createBaseFor = require('./_createBaseFor');
 
 /**
  * This function is like `baseFor` except that it iterates over properties

_baseFunctions.js

@@ -1,5 +1,5 @@
-var arrayFilter = require('./arrayFilter'),
-    isFunction = require('../isFunction');
+var arrayFilter = require('./_arrayFilter'),
+    isFunction = require('./isFunction');
 
 /**
  * The base implementation of `_.functions` which creates an array of

_baseGet.js

@@ -1,5 +1,5 @@
-var baseToPath = require('./baseToPath'),
-    isKey = require('./isKey');
+var baseToPath = require('./_baseToPath'),
+    isKey = require('./_isKey');
 
 /**
  * The base implementation of `_.get` without support for default values.

_baseHas.js

@@ -1,5 +1,5 @@
 /** Used for built-in method references. */
-var objectProto = global.Object.prototype;
+var objectProto = Object.prototype;
 
 /** Used to check objects for own properties. */
 var hasOwnProperty = objectProto.hasOwnProperty;

_baseIndexOf.js

@@ -1,4 +1,4 @@
-var indexOfNaN = require('./indexOfNaN');
+var indexOfNaN = require('./_indexOfNaN');
 
 /**
  * The base implementation of `_.indexOf` without `fromIndex` bounds checks.

_baseIntersection.js

@@ -1,9 +1,9 @@
-var SetCache = require('./SetCache'),
-    arrayIncludes = require('./arrayIncludes'),
-    arrayIncludesWith = require('./arrayIncludesWith'),
-    arrayMap = require('./arrayMap'),
-    baseUnary = require('./baseUnary'),
-    cacheHas = require('./cacheHas');
+var SetCache = require('./_SetCache'),
+    arrayIncludes = require('./_arrayIncludes'),
+    arrayIncludesWith = require('./_arrayIncludesWith'),
+    arrayMap = require('./_arrayMap'),
+    baseUnary = require('./_baseUnary'),
+    cacheHas = require('./_cacheHas');
 
 /**
  * The base implementation of methods like `_.intersection`, without support

_baseInverter.js

@@ -0,0 +1,21 @@
+var baseForOwn = require('./_baseForOwn');
+
+/**
+ * The base implementation of `_.invert` and `_.invertBy` which inverts
+ * `object` with values transformed by `iteratee` and set by `setter`.
+ *
+ * @private
+ * @param {Object} object The object to iterate over.
+ * @param {Function} setter The function to set `accumulator` values.
+ * @param {Function} iteratee The iteratee to transform values.
+ * @param {Object} accumulator The initial inverted object.
+ * @returns {Function} Returns `accumulator`.
+ */
+function baseInverter(object, setter, iteratee, accumulator) {
+  baseForOwn(object, function(value, key, object) {
+    setter(accumulator, iteratee(value), key, object);
+  });
+  return accumulator;
+}
+
+module.exports = baseInverter;

_baseInvoke.js

@@ -1,14 +1,13 @@
-var apply = require('./apply'),
-    baseToPath = require('./baseToPath'),
-    isKey = require('./isKey'),
-    last = require('../last'),
-    parent = require('./parent');
+var apply = require('./_apply'),
+    baseToPath = require('./_baseToPath'),
+    isKey = require('./_isKey'),
+    last = require('./last'),
+    parent = require('./_parent');
 
 /**
  * The base implementation of `_.invoke` without support for individual
  * method arguments.
  *
- *
  * @private
  * @param {Object} object The object to query.
  * @param {Array|string} path The path of the method to invoke.

_baseIsEqual.js

@@ -1,6 +1,6 @@
-var baseIsEqualDeep = require('./baseIsEqualDeep'),
-    isObject = require('../isObject'),
-    isObjectLike = require('../isObjectLike');
+var baseIsEqualDeep = require('./_baseIsEqualDeep'),
+    isObject = require('./isObject'),
+    isObjectLike = require('./isObjectLike');
 
 /**
  * The base implementation of `_.isEqual` which supports partial comparisons

_baseIsEqualDeep.js

@@ -1,11 +1,11 @@
-var Stack = require('./Stack'),
-    equalArrays = require('./equalArrays'),
-    equalByTag = require('./equalByTag'),
-    equalObjects = require('./equalObjects'),
-    getTag = require('./getTag'),
-    isArray = require('../isArray'),
-    isHostObject = require('./isHostObject'),
-    isTypedArray = require('../isTypedArray');
+var Stack = require('./_Stack'),
+    equalArrays = require('./_equalArrays'),
+    equalByTag = require('./_equalByTag'),
+    equalObjects = require('./_equalObjects'),
+    getTag = require('./_getTag'),
+    isArray = require('./isArray'),
+    isHostObject = require('./_isHostObject'),
+    isTypedArray = require('./isTypedArray');
 
 /** Used to compose bitmasks for comparison styles. */
 var PARTIAL_COMPARE_FLAG = 2;
@@ -16,7 +16,7 @@ var argsTag = '[object Arguments]',
     objectTag = '[object Object]';
 
 /** Used for built-in method references. */
-var objectProto = global.Object.prototype;
+var objectProto = Object.prototype;
 
 /** Used to check objects for own properties. */
 var hasOwnProperty = objectProto.hasOwnProperty;

_baseIsMatch.js

@@ -1,5 +1,5 @@
-var Stack = require('./Stack'),
-    baseIsEqual = require('./baseIsEqual');
+var Stack = require('./_Stack'),
+    baseIsEqual = require('./_baseIsEqual');
 
 /** Used to compose bitmasks for comparison styles. */
 var UNORDERED_COMPARE_FLAG = 1,
@@ -47,7 +47,10 @@ function baseIsMatch(object, source, matchData, customizer) {
       var stack = new Stack,
           result = customizer ? customizer(objValue, srcValue, key, object, source, stack) : undefined;
 
-      if (!(result === undefined ? baseIsEqual(srcValue, objValue, customizer, UNORDERED_COMPARE_FLAG | PARTIAL_COMPARE_FLAG, stack) : result)) {
+      if (!(result === undefined
+            ? baseIsEqual(srcValue, objValue, customizer, UNORDERED_COMPARE_FLAG | PARTIAL_COMPARE_FLAG, stack)
+            : result
+          )) {
         return false;
       }
     }

_baseIteratee.js

@@ -1,8 +1,8 @@
-var baseMatches = require('./baseMatches'),
-    baseMatchesProperty = require('./baseMatchesProperty'),
-    identity = require('../identity'),
-    isArray = require('../isArray'),
-    property = require('../property');
+var baseMatches = require('./_baseMatches'),
+    baseMatchesProperty = require('./_baseMatchesProperty'),
+    identity = require('./identity'),
+    isArray = require('./isArray'),
+    property = require('./property');
 
 /**
  * The base implementation of `_.iteratee`.

_baseKeysIn.js

@@ -1,8 +1,8 @@
-var Reflect = require('./Reflect'),
-    iteratorToArray = require('./iteratorToArray');
+var Reflect = require('./_Reflect'),
+    iteratorToArray = require('./_iteratorToArray');
 
 /** Used for built-in method references. */
-var objectProto = global.Object.prototype;
+var objectProto = Object.prototype;
 
 /** Built-in value references. */
 var enumerate = Reflect ? Reflect.enumerate : undefined,

_baseMap.js

@@ -1,5 +1,5 @@
-var baseEach = require('./baseEach'),
-    isArrayLike = require('../isArrayLike');
+var baseEach = require('./_baseEach'),
+    isArrayLike = require('./isArrayLike');
 
 /**
  * The base implementation of `_.map` without support for iteratee shorthands.

_baseMatches.js

@@ -1,5 +1,5 @@
-var baseIsMatch = require('./baseIsMatch'),
-    getMatchData = require('./getMatchData');
+var baseIsMatch = require('./_baseIsMatch'),
+    getMatchData = require('./_getMatchData');
 
 /**
  * The base implementation of `_.matches` which doesn't clone `source`.

_baseMatchesProperty.js

@@ -1,6 +1,6 @@
-var baseIsEqual = require('./baseIsEqual'),
-    get = require('../get'),
-    hasIn = require('../hasIn');
+var baseIsEqual = require('./_baseIsEqual'),
+    get = require('./get'),
+    hasIn = require('./hasIn');
 
 /** Used to compose bitmasks for comparison styles. */
 var UNORDERED_COMPARE_FLAG = 1,

_baseMerge.js

@@ -1,11 +1,11 @@
-var Stack = require('./Stack'),
-    arrayEach = require('./arrayEach'),
-    assignMergeValue = require('./assignMergeValue'),
-    baseMergeDeep = require('./baseMergeDeep'),
-    isArray = require('../isArray'),
-    isObject = require('../isObject'),
-    isTypedArray = require('../isTypedArray'),
-    keysIn = require('../keysIn');
+var Stack = require('./_Stack'),
+    arrayEach = require('./_arrayEach'),
+    assignMergeValue = require('./_assignMergeValue'),
+    baseMergeDeep = require('./_baseMergeDeep'),
+    isArray = require('./isArray'),
+    isObject = require('./isObject'),
+    isTypedArray = require('./isTypedArray'),
+    keysIn = require('./keysIn');
 
 /**
  * The base implementation of `_.merge` without support for multiple sources.
@@ -13,10 +13,11 @@ var Stack = require('./Stack'),
  * @private
  * @param {Object} object The destination object.
  * @param {Object} source The source object.
+ * @param {number} srcIndex The index of `source`.
  * @param {Function} [customizer] The function to customize merged values.
  * @param {Object} [stack] Tracks traversed source values and their merged counterparts.
  */
-function baseMerge(object, source, customizer, stack) {
+function baseMerge(object, source, srcIndex, customizer, stack) {
   if (object === source) {
     return;
   }
@@ -28,7 +29,7 @@ function baseMerge(object, source, customizer, stack) {
     }
     if (isObject(srcValue)) {
       stack || (stack = new Stack);
-      baseMergeDeep(object, source, key, baseMerge, customizer, stack);
+      baseMergeDeep(object, source, key, srcIndex, baseMerge, customizer, stack);
     }
     else {
       var newValue = customizer ? customizer(object[key], srcValue, (key + ''), object, source, stack) : undefined;

_baseMergeDeep.js

@@ -0,0 +1,78 @@
+var assignMergeValue = require('./_assignMergeValue'),
+    baseClone = require('./_baseClone'),
+    copyArray = require('./_copyArray'),
+    isArguments = require('./isArguments'),
+    isArray = require('./isArray'),
+    isArrayLikeObject = require('./isArrayLikeObject'),
+    isFunction = require('./isFunction'),
+    isObject = require('./isObject'),
+    isPlainObject = require('./isPlainObject'),
+    isTypedArray = require('./isTypedArray'),
+    toPlainObject = require('./toPlainObject');
+
+/**
+ * A specialized version of `baseMerge` for arrays and objects which performs
+ * deep merges and tracks traversed objects enabling objects with circular
+ * references to be merged.
+ *
+ * @private
+ * @param {Object} object The destination object.
+ * @param {Object} source The source object.
+ * @param {string} key The key of the value to merge.
+ * @param {number} srcIndex The index of `source`.
+ * @param {Function} mergeFunc The function to merge values.
+ * @param {Function} [customizer] The function to customize assigned values.
+ * @param {Object} [stack] Tracks traversed source values and their merged counterparts.
+ */
+function baseMergeDeep(object, source, key, srcIndex, mergeFunc, customizer, stack) {
+  var objValue = object[key],
+      srcValue = source[key],
+      stacked = stack.get(srcValue);
+
+  if (stacked) {
+    assignMergeValue(object, key, stacked);
+    return;
+  }
+  var newValue = customizer ? customizer(objValue, srcValue, (key + ''), object, source, stack) : undefined,
+      isCommon = newValue === undefined;
+
+  if (isCommon) {
+    newValue = srcValue;
+    if (isArray(srcValue) || isTypedArray(srcValue)) {
+      if (isArray(objValue)) {
+        newValue = srcIndex ? copyArray(objValue) : objValue;
+      }
+      else if (isArrayLikeObject(objValue)) {
+        newValue = copyArray(objValue);
+      }
+      else {
+        isCommon = false;
+        newValue = baseClone(srcValue);
+      }
+    }
+    else if (isPlainObject(srcValue) || isArguments(srcValue)) {
+      if (isArguments(objValue)) {
+        newValue = toPlainObject(objValue);
+      }
+      else if (!isObject(objValue) || (srcIndex && isFunction(objValue))) {
+        isCommon = false;
+        newValue = baseClone(srcValue);
+      }
+      else {
+        newValue = srcIndex ? baseClone(objValue) : objValue;
+      }
+    }
+    else {
+      isCommon = false;
+    }
+  }
+  stack.set(srcValue, newValue);
+
+  if (isCommon) {
+    // Recursively merge objects and arrays (susceptible to call stack limits).
+    mergeFunc(newValue, srcValue, srcIndex, customizer, stack);
+  }
+  assignMergeValue(object, key, newValue);
+}
+
+module.exports = baseMergeDeep;

_baseOrderBy.js

@@ -1,8 +1,8 @@
-var arrayMap = require('./arrayMap'),
-    baseIteratee = require('./baseIteratee'),
-    baseMap = require('./baseMap'),
-    baseSortBy = require('./baseSortBy'),
-    compareMultiple = require('./compareMultiple');
+var arrayMap = require('./_arrayMap'),
+    baseIteratee = require('./_baseIteratee'),
+    baseMap = require('./_baseMap'),
+    baseSortBy = require('./_baseSortBy'),
+    compareMultiple = require('./_compareMultiple');
 
 /**
  * The base implementation of `_.orderBy` without param guards.

_basePick.js

@@ -1,4 +1,4 @@
-var arrayReduce = require('./arrayReduce');
+var arrayReduce = require('./_arrayReduce');
 
 /**
  * The base implementation of `_.pick` without support for individual

_basePickBy.js

@@ -1,4 +1,4 @@
-var baseForIn = require('./baseForIn');
+var baseForIn = require('./_baseForIn');
 
 /**
  * The base implementation of  `_.pickBy` without support for iteratee shorthands.
@@ -11,7 +11,7 @@ var baseForIn = require('./baseForIn');
 function basePickBy(object, predicate) {
   var result = {};
   baseForIn(object, function(value, key) {
-    if (predicate(value)) {
+    if (predicate(value, key)) {
       result[key] = value;
     }
   });

_basePropertyDeep.js

@@ -1,4 +1,4 @@
-var baseGet = require('./baseGet');
+var baseGet = require('./_baseGet');
 
 /**
  * A specialized version of `baseProperty` which supports deep paths.

_basePullAll.js

@@ -1,4 +1,4 @@
-var basePullAllBy = require('./basePullAllBy');
+var basePullAllBy = require('./_basePullAllBy');
 
 /**
  * The base implementation of `_.pullAll`.

_basePullAllBy.js

@@ -1,8 +1,8 @@
-var arrayMap = require('./arrayMap'),
-    baseIndexOf = require('./baseIndexOf');
+var arrayMap = require('./_arrayMap'),
+    baseIndexOf = require('./_baseIndexOf');
 
 /** Used for built-in method references. */
-var arrayProto = global.Array.prototype;
+var arrayProto = Array.prototype;
 
 /** Built-in value references. */
 var splice = arrayProto.splice;

_basePullAt.js

@@ -1,11 +1,11 @@
-var baseToPath = require('./baseToPath'),
-    isIndex = require('./isIndex'),
-    isKey = require('./isKey'),
-    last = require('../last'),
-    parent = require('./parent');
+var baseToPath = require('./_baseToPath'),
+    isIndex = require('./_isIndex'),
+    isKey = require('./_isKey'),
+    last = require('./last'),
+    parent = require('./_parent');
 
 /** Used for built-in method references. */
-var arrayProto = global.Array.prototype;
+var arrayProto = Array.prototype;
 
 /** Built-in value references. */
 var splice = arrayProto.splice;

_baseReduce.js

@@ -1,20 +1,19 @@
 /**
  * The base implementation of `_.reduce` and `_.reduceRight`, without support
- * for iteratee shorthands, which iterates over `collection` using the provided
- * `eachFunc`.
+ * for iteratee shorthands, which iterates over `collection` using `eachFunc`.
  *
  * @private
  * @param {Array|Object} collection The collection to iterate over.
  * @param {Function} iteratee The function invoked per iteration.
  * @param {*} accumulator The initial value.
- * @param {boolean} initFromCollection Specify using the first or last element of `collection` as the initial value.
+ * @param {boolean} initAccum Specify using the first or last element of `collection` as the initial value.
  * @param {Function} eachFunc The function to iterate over `collection`.
  * @returns {*} Returns the accumulated value.
  */
-function baseReduce(collection, iteratee, accumulator, initFromCollection, eachFunc) {
+function baseReduce(collection, iteratee, accumulator, initAccum, eachFunc) {
   eachFunc(collection, function(value, index, collection) {
-    accumulator = initFromCollection
-      ? (initFromCollection = false, value)
+    accumulator = initAccum
+      ? (initAccum = false, value)
       : iteratee(accumulator, value, index, collection);
   });
   return accumulator;

_baseSet.js

@@ -1,8 +1,8 @@
-var assignValue = require('./assignValue'),
-    baseToPath = require('./baseToPath'),
-    isIndex = require('./isIndex'),
-    isKey = require('./isKey'),
-    isObject = require('../isObject');
+var assignValue = require('./_assignValue'),
+    baseToPath = require('./_baseToPath'),
+    isIndex = require('./_isIndex'),
+    isKey = require('./_isKey'),
+    isObject = require('./isObject');
 
 /**
  * The base implementation of `_.set`.

_baseSetData.js

@@ -1,5 +1,5 @@
-var identity = require('../identity'),
-    metaMap = require('./metaMap');
+var identity = require('./identity'),
+    metaMap = require('./_metaMap');
 
 /**
  * The base implementation of `setData` without support for hot loop detection.

_baseSome.js

@@ -1,4 +1,4 @@
-var baseEach = require('./baseEach');
+var baseEach = require('./_baseEach');
 
 /**
  * The base implementation of `_.some` without support for iteratee shorthands.

_baseSortedIndex.js

@@ -1,5 +1,5 @@
-var baseSortedIndexBy = require('./baseSortedIndexBy'),
-    identity = require('../identity');
+var baseSortedIndexBy = require('./_baseSortedIndexBy'),
+    identity = require('./identity');
 
 /** Used as references for the maximum length and index of an array. */
 var MAX_ARRAY_LENGTH = 4294967295,

_baseSortedUniq.js

@@ -1,4 +1,4 @@
-var baseSortedUniqBy = require('./baseSortedUniqBy');
+var baseSortedUniqBy = require('./_baseSortedUniqBy');
 
 /**
  * The base implementation of `_.sortedUniq`.