Fix prototype pollution in _.unset and _.omit (#6063)

Prevent prototype pollution on baseUnset function by:
- Blocking "__proto__" if not an own property
- Blocking "constructor.prototype" chains (except when starting at primitive root)
- Skipping non-string keys

See: https://github.com/lodash/lodash/security/advisories/GHSA-xxjr-mmjv-4gpg

LICENSE

@@ -1,4 +1,4 @@
-Copyright jQuery Foundation and other contributors <https://jquery.org/>
+Copyright OpenJS Foundation and other contributors <https://openjsf.org/>
 
 Based on Underscore.js, copyright Jeremy Ashkenas,
 DocumentCloud and Investigative Reporters & Editors <http://underscorejs.org/>

README.md

@@ -1,12 +1,12 @@
-# lodash v4.8.2
+# lodash v4.17.21
 
 The [Lodash](https://lodash.com/) library exported as [Node.js](https://nodejs.org/) modules.
 
 ## Installation
 
 Using npm:
-```bash
+```shell
-$ {sudo -H} npm i -g npm
+$ npm i -g npm
 $ npm i --save lodash
 ```
 
@@ -16,25 +16,24 @@ In Node.js:
 var _ = require('lodash');
 // Load the core build.
 var _ = require('lodash/core');
-// Load the fp build for immutable auto-curried iteratee-first data-last methods.
+// Load the FP build for immutable auto-curried iteratee-first data-last methods.
 var fp = require('lodash/fp');
 
-// Load a method category.
+// Load method categories.
 var array = require('lodash/array');
 var object = require('lodash/fp/object');
 
-// Load a single method for smaller builds with browserify/rollup/webpack.
+// Cherry-pick methods for smaller browserify/rollup/webpack bundles.
-var chunk = require('lodash/chunk');
+var at = require('lodash/at');
-var extend = require('lodash/fp/extend');
+var curryN = require('lodash/fp/curryN');
 ```
 
-See the [package source](https://github.com/lodash/lodash/tree/4.8.2-npm) for more details.
+See the [package source](https://github.com/lodash/lodash/tree/4.17.21-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>
+Install [n_](https://www.npmjs.com/package/n_) for Lodash use in the Node.js < 6 REPL.
-Install [n_](https://www.npmjs.com/package/n_) for a REPL that includes `lodash` by default.
 
 ## Support
 
-Tested in Chrome 48-49, Firefox 44-45, IE 9-11, Edge 13, Safari 8-9, Node.js 0.10, 0.12, 4, & 5, & PhantomJS 1.9.8.<br>
+Tested in Chrome 74-75, Firefox 66-67, IE 11, Edge 18, Safari 11-12, & Node.js 8-12.<br>
 Automated [browser](https://saucelabs.com/u/lodash) & [CI](https://travis-ci.org/lodash/lodash/) test runs are available.

_Hash.js

@@ -1,18 +1,32 @@
-var nativeCreate = require('./_nativeCreate');
+var hashClear = require('./_hashClear'),
-
+    hashDelete = require('./_hashDelete'),
-/** Used for built-in method references. */
+    hashGet = require('./_hashGet'),
-var objectProto = Object.prototype;
+    hashHas = require('./_hashHas'),
+    hashSet = require('./_hashSet');
 
 /**
- * Creates an hash object.
+ * Creates a hash object.
  *
  * @private
  * @constructor
- * @returns {Object} Returns the new hash object.
+ * @param {Array} [entries] The key-value pairs to cache.
  */
-function Hash() {}
+function Hash(entries) {
+  var index = -1,
+      length = entries == null ? 0 : entries.length;
 
-// Avoid inheriting from `Object.prototype` when possible.
+  this.clear();
-Hash.prototype = nativeCreate ? nativeCreate(null) : objectProto;
+  while (++index < length) {
+    var entry = entries[index];
+    this.set(entry[0], entry[1]);
+  }
+}
+
+// Add methods to `Hash`.
+Hash.prototype.clear = hashClear;
+Hash.prototype['delete'] = hashDelete;
+Hash.prototype.get = hashGet;
+Hash.prototype.has = hashHas;
+Hash.prototype.set = hashSet;
 
 module.exports = Hash;

_ListCache.js

@@ -0,0 +1,32 @@
+var listCacheClear = require('./_listCacheClear'),
+    listCacheDelete = require('./_listCacheDelete'),
+    listCacheGet = require('./_listCacheGet'),
+    listCacheHas = require('./_listCacheHas'),
+    listCacheSet = require('./_listCacheSet');
+
+/**
+ * Creates an list cache object.
+ *
+ * @private
+ * @constructor
+ * @param {Array} [entries] The key-value pairs to cache.
+ */
+function ListCache(entries) {
+  var index = -1,
+      length = entries == null ? 0 : entries.length;
+
+  this.clear();
+  while (++index < length) {
+    var entry = entries[index];
+    this.set(entry[0], entry[1]);
+  }
+}
+
+// Add methods to `ListCache`.
+ListCache.prototype.clear = listCacheClear;
+ListCache.prototype['delete'] = listCacheDelete;
+ListCache.prototype.get = listCacheGet;
+ListCache.prototype.has = listCacheHas;
+ListCache.prototype.set = listCacheSet;
+
+module.exports = ListCache;

_MapCache.js

@@ -1,32 +1,32 @@
-var mapClear = require('./_mapClear'),
+var mapCacheClear = require('./_mapCacheClear'),
-    mapDelete = require('./_mapDelete'),
+    mapCacheDelete = require('./_mapCacheDelete'),
-    mapGet = require('./_mapGet'),
+    mapCacheGet = require('./_mapCacheGet'),
-    mapHas = require('./_mapHas'),
+    mapCacheHas = require('./_mapCacheHas'),
-    mapSet = require('./_mapSet');
+    mapCacheSet = require('./_mapCacheSet');
 
 /**
  * Creates a map cache object to store key-value pairs.
  *
  * @private
  * @constructor
- * @param {Array} [values] The values to cache.
+ * @param {Array} [entries] The key-value pairs to cache.
  */
-function MapCache(values) {
+function MapCache(entries) {
   var index = -1,
-      length = values ? values.length : 0;
+      length = entries == null ? 0 : entries.length;
 
   this.clear();
   while (++index < length) {
-    var entry = values[index];
+    var entry = entries[index];
     this.set(entry[0], entry[1]);
   }
 }
 
 // Add methods to `MapCache`.
-MapCache.prototype.clear = mapClear;
+MapCache.prototype.clear = mapCacheClear;
-MapCache.prototype['delete'] = mapDelete;
+MapCache.prototype['delete'] = mapCacheDelete;
-MapCache.prototype.get = mapGet;
+MapCache.prototype.get = mapCacheGet;
-MapCache.prototype.has = mapHas;
+MapCache.prototype.has = mapCacheHas;
-MapCache.prototype.set = mapSet;
+MapCache.prototype.set = mapCacheSet;
 
 module.exports = MapCache;

_Reflect.js

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

_SetCache.js

@@ -1,9 +1,10 @@
 var MapCache = require('./_MapCache'),
-    cachePush = require('./_cachePush');
+    setCacheAdd = require('./_setCacheAdd'),
+    setCacheHas = require('./_setCacheHas');
 
 /**
  *
- * Creates a set cache object to store unique values.
+ * Creates an array cache object to store unique values.
  *
  * @private
  * @constructor
@@ -11,15 +12,16 @@ var MapCache = require('./_MapCache'),
  */
 function SetCache(values) {
   var index = -1,
-      length = values ? values.length : 0;
+      length = values == null ? 0 : values.length;
 
   this.__data__ = new MapCache;
   while (++index < length) {
-    this.push(values[index]);
+    this.add(values[index]);
   }
 }
 
 // Add methods to `SetCache`.
-SetCache.prototype.push = cachePush;
+SetCache.prototype.add = SetCache.prototype.push = setCacheAdd;
+SetCache.prototype.has = setCacheHas;
 
 module.exports = SetCache;

_Stack.js

@@ -1,4 +1,5 @@
-var stackClear = require('./_stackClear'),
+var ListCache = require('./_ListCache'),
+    stackClear = require('./_stackClear'),
     stackDelete = require('./_stackDelete'),
     stackGet = require('./_stackGet'),
     stackHas = require('./_stackHas'),
@@ -9,17 +10,11 @@ var stackClear = require('./_stackClear'),
  *
  * @private
  * @constructor
- * @param {Array} [values] The values to cache.
+ * @param {Array} [entries] The key-value pairs to cache.
  */
-function Stack(values) {
+function Stack(entries) {
-  var index = -1,
+  var data = this.__data__ = new ListCache(entries);
-      length = values ? values.length : 0;
+  this.size = data.size;
-
-  this.clear();
-  while (++index < length) {
-    var entry = values[index];
-    this.set(entry[0], entry[1]);
-  }
 }
 
 // Add methods to `Stack`.

_addMapEntry.js

@@ -1,15 +0,0 @@
-/**
- * Adds the key-value `pair` to `map`.
- *
- * @private
- * @param {Object} map The map to modify.
- * @param {Array} pair The key-value pair to add.
- * @returns {Object} Returns `map`.
- */
-function addMapEntry(map, pair) {
-  // Don't return `Map#set` because it doesn't return the map instance in IE 11.
-  map.set(pair[0], pair[1]);
-  return map;
-}
-
-module.exports = addMapEntry;

_addSetEntry.js

@@ -1,14 +0,0 @@
-/**
- * Adds `value` to `set`.
- *
- * @private
- * @param {Object} set The set to modify.
- * @param {*} value The value to add.
- * @returns {Object} Returns `set`.
- */
-function addSetEntry(set, value) {
-  set.add(value);
-  return set;
-}
-
-module.exports = addSetEntry;

_apply.js

@@ -9,8 +9,7 @@
  * @returns {*} Returns the result of `func`.
  */
 function apply(func, thisArg, args) {
-  var length = args.length;
+  switch (args.length) {
-  switch (length) {
     case 0: return func.call(thisArg);
     case 1: return func.call(thisArg, args[0]);
     case 2: return func.call(thisArg, args[0], args[1]);

_arrayAggregator.js

@@ -2,7 +2,7 @@
  * A specialized version of `baseAggregator` for arrays.
  *
  * @private
- * @param {Array} array The array to iterate over.
+ * @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.
@@ -10,7 +10,7 @@
  */
 function arrayAggregator(array, setter, iteratee, accumulator) {
   var index = -1,
-      length = array.length;
+      length = array == null ? 0 : array.length;
 
   while (++index < length) {
     var value = array[index];

_arrayConcat.js

@@ -1,25 +0,0 @@
-/**
- * Creates a new array concatenating `array` with `other`.
- *
- * @private
- * @param {Array} array The first array to concatenate.
- * @param {Array} other The second array to concatenate.
- * @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;
-}
-
-module.exports = arrayConcat;

_arrayEach.js

@@ -3,13 +3,13 @@
  * iteratee shorthands.
  *
  * @private
- * @param {Array} array The array to iterate over.
+ * @param {Array} [array] The array to iterate over.
  * @param {Function} iteratee The function invoked per iteration.
  * @returns {Array} Returns `array`.
  */
 function arrayEach(array, iteratee) {
   var index = -1,
-      length = array.length;
+      length = array == null ? 0 : array.length;
 
   while (++index < length) {
     if (iteratee(array[index], index, array) === false) {

_arrayEachRight.js

@@ -3,12 +3,12 @@
  * iteratee shorthands.
  *
  * @private
- * @param {Array} array The array to iterate over.
+ * @param {Array} [array] The array to iterate over.
  * @param {Function} iteratee The function invoked per iteration.
  * @returns {Array} Returns `array`.
  */
 function arrayEachRight(array, iteratee) {
-  var length = array.length;
+  var length = array == null ? 0 : array.length;
 
   while (length--) {
     if (iteratee(array[length], length, array) === false) {

_arrayEvery.js

@@ -3,14 +3,14 @@
  * iteratee shorthands.
  *
  * @private
- * @param {Array} array The array to iterate over.
+ * @param {Array} [array] The array to iterate over.
  * @param {Function} predicate The function invoked per iteration.
  * @returns {boolean} Returns `true` if all elements pass the predicate check,
  *  else `false`.
  */
 function arrayEvery(array, predicate) {
   var index = -1,
-      length = array.length;
+      length = array == null ? 0 : array.length;
 
   while (++index < length) {
     if (!predicate(array[index], index, array)) {

_arrayFilter.js

@@ -3,13 +3,13 @@
  * iteratee shorthands.
  *
  * @private
- * @param {Array} array The array to iterate over.
+ * @param {Array} [array] The array to iterate over.
  * @param {Function} predicate The function invoked per iteration.
  * @returns {Array} Returns the new filtered array.
  */
 function arrayFilter(array, predicate) {
   var index = -1,
-      length = array.length,
+      length = array == null ? 0 : array.length,
       resIndex = 0,
       result = [];
 

_arrayIncludes.js

@@ -5,12 +5,13 @@ var baseIndexOf = require('./_baseIndexOf');
  * specifying an index to search from.
  *
  * @private
- * @param {Array} array The array to search.
+ * @param {Array} [array] The array to inspect.
  * @param {*} target The value to search for.
  * @returns {boolean} Returns `true` if `target` is found, else `false`.
  */
 function arrayIncludes(array, value) {
-  return !!array.length && baseIndexOf(array, value, 0) > -1;
+  var length = array == null ? 0 : array.length;
+  return !!length && baseIndexOf(array, value, 0) > -1;
 }
 
 module.exports = arrayIncludes;

_arrayIncludesWith.js

@@ -2,14 +2,14 @@
  * This function is like `arrayIncludes` except that it accepts a comparator.
  *
  * @private
- * @param {Array} array The array to search.
+ * @param {Array} [array] The array to inspect.
  * @param {*} target The value to search for.
  * @param {Function} comparator The comparator invoked per element.
  * @returns {boolean} Returns `true` if `target` is found, else `false`.
  */
 function arrayIncludesWith(array, value, comparator) {
   var index = -1,
-      length = array.length;
+      length = array == null ? 0 : array.length;
 
   while (++index < length) {
     if (comparator(value, array[index])) {

_arrayLikeKeys.js

@@ -0,0 +1,49 @@
+var baseTimes = require('./_baseTimes'),
+    isArguments = require('./isArguments'),
+    isArray = require('./isArray'),
+    isBuffer = require('./isBuffer'),
+    isIndex = require('./_isIndex'),
+    isTypedArray = require('./isTypedArray');
+
+/** Used for built-in method references. */
+var objectProto = Object.prototype;
+
+/** Used to check objects for own properties. */
+var hasOwnProperty = objectProto.hasOwnProperty;
+
+/**
+ * Creates an array of the enumerable property names of the array-like `value`.
+ *
+ * @private
+ * @param {*} value The value to query.
+ * @param {boolean} inherited Specify returning inherited property names.
+ * @returns {Array} Returns the array of property names.
+ */
+function arrayLikeKeys(value, inherited) {
+  var isArr = isArray(value),
+      isArg = !isArr && isArguments(value),
+      isBuff = !isArr && !isArg && isBuffer(value),
+      isType = !isArr && !isArg && !isBuff && isTypedArray(value),
+      skipIndexes = isArr || isArg || isBuff || isType,
+      result = skipIndexes ? baseTimes(value.length, String) : [],
+      length = result.length;
+
+  for (var key in value) {
+    if ((inherited || hasOwnProperty.call(value, key)) &&
+        !(skipIndexes && (
+           // Safari 9 has enumerable `arguments.length` in strict mode.
+           key == 'length' ||
+           // Node.js 0.10 has enumerable non-index properties on buffers.
+           (isBuff && (key == 'offset' || key == 'parent')) ||
+           // PhantomJS 2 has enumerable non-index properties on typed arrays.
+           (isType && (key == 'buffer' || key == 'byteLength' || key == 'byteOffset')) ||
+           // Skip index properties.
+           isIndex(key, length)
+        ))) {
+      result.push(key);
+    }
+  }
+  return result;
+}
+
+module.exports = arrayLikeKeys;

_arrayMap.js

@@ -3,13 +3,13 @@
  * shorthands.
  *
  * @private
- * @param {Array} array The array to iterate over.
+ * @param {Array} [array] The array to iterate over.
  * @param {Function} iteratee The function invoked per iteration.
  * @returns {Array} Returns the new mapped array.
  */
 function arrayMap(array, iteratee) {
   var index = -1,
-      length = array.length,
+      length = array == null ? 0 : array.length,
       result = Array(length);
 
   while (++index < length) {

_arrayReduce.js

@@ -3,7 +3,7 @@
  * iteratee shorthands.
  *
  * @private
- * @param {Array} array The array to iterate over.
+ * @param {Array} [array] The array to iterate over.
  * @param {Function} iteratee The function invoked per iteration.
  * @param {*} [accumulator] The initial value.
  * @param {boolean} [initAccum] Specify using the first element of `array` as
@@ -12,7 +12,7 @@
  */
 function arrayReduce(array, iteratee, accumulator, initAccum) {
   var index = -1,
-      length = array.length;
+      length = array == null ? 0 : array.length;
 
   if (initAccum && length) {
     accumulator = array[++index];

_arrayReduceRight.js

@@ -3,7 +3,7 @@
  * iteratee shorthands.
  *
  * @private
- * @param {Array} array The array to iterate over.
+ * @param {Array} [array] The array to iterate over.
  * @param {Function} iteratee The function invoked per iteration.
  * @param {*} [accumulator] The initial value.
  * @param {boolean} [initAccum] Specify using the last element of `array` as
@@ -11,7 +11,7 @@
  * @returns {*} Returns the accumulated value.
  */
 function arrayReduceRight(array, iteratee, accumulator, initAccum) {
-  var length = array.length;
+  var length = array == null ? 0 : array.length;
   if (initAccum && length) {
     accumulator = array[--length];
   }

_arraySample.js

@@ -0,0 +1,15 @@
+var baseRandom = require('./_baseRandom');
+
+/**
+ * A specialized version of `_.sample` for arrays.
+ *
+ * @private
+ * @param {Array} array The array to sample.
+ * @returns {*} Returns the random element.
+ */
+function arraySample(array) {
+  var length = array.length;
+  return length ? array[baseRandom(0, length - 1)] : undefined;
+}
+
+module.exports = arraySample;

_arraySampleSize.js

@@ -0,0 +1,17 @@
+var baseClamp = require('./_baseClamp'),
+    copyArray = require('./_copyArray'),
+    shuffleSelf = require('./_shuffleSelf');
+
+/**
+ * A specialized version of `_.sampleSize` for arrays.
+ *
+ * @private
+ * @param {Array} array The array to sample.
+ * @param {number} n The number of elements to sample.
+ * @returns {Array} Returns the random elements.
+ */
+function arraySampleSize(array, n) {
+  return shuffleSelf(copyArray(array), baseClamp(n, 0, array.length));
+}
+
+module.exports = arraySampleSize;

_arrayShuffle.js

@@ -0,0 +1,15 @@
+var copyArray = require('./_copyArray'),
+    shuffleSelf = require('./_shuffleSelf');
+
+/**
+ * A specialized version of `_.shuffle` for arrays.
+ *
+ * @private
+ * @param {Array} array The array to shuffle.
+ * @returns {Array} Returns the new shuffled array.
+ */
+function arrayShuffle(array) {
+  return shuffleSelf(copyArray(array));
+}
+
+module.exports = arrayShuffle;

_arraySome.js

@@ -3,14 +3,14 @@
  * shorthands.
  *
  * @private
- * @param {Array} array The array to iterate over.
+ * @param {Array} [array] The array to iterate over.
  * @param {Function} predicate The function invoked per iteration.
  * @returns {boolean} Returns `true` if any element passes the predicate check,
  *  else `false`.
  */
 function arraySome(array, predicate) {
   var index = -1,
-      length = array.length;
+      length = array == null ? 0 : array.length;
 
   while (++index < length) {
     if (predicate(array[index], index, array)) {

_asciiSize.js

@@ -0,0 +1,12 @@
+var baseProperty = require('./_baseProperty');
+
+/**
+ * Gets the size of an ASCII `string`.
+ *
+ * @private
+ * @param {string} string The string inspect.
+ * @returns {number} Returns the string size.
+ */
+var asciiSize = baseProperty('length');
+
+module.exports = asciiSize;

_asciiToArray.js

@@ -0,0 +1,12 @@
+/**
+ * Converts an ASCII `string` to an array.
+ *
+ * @private
+ * @param {string} string The string to convert.
+ * @returns {Array} Returns the converted array.
+ */
+function asciiToArray(string) {
+  return string.split('');
+}
+
+module.exports = asciiToArray;

_asciiWords.js

@@ -0,0 +1,15 @@
+/** Used to match words composed of alphanumeric characters. */
+var reAsciiWord = /[^\x00-\x2f\x3a-\x40\x5b-\x60\x7b-\x7f]+/g;
+
+/**
+ * Splits an ASCII `string` into an array of its words.
+ *
+ * @private
+ * @param {string} The string to inspect.
+ * @returns {Array} Returns the words of `string`.
+ */
+function asciiWords(string) {
+  return string.match(reAsciiWord) || [];
+}
+
+module.exports = asciiWords;

_assignMergeValue.js

@@ -1,4 +1,5 @@
-var eq = require('./eq');
+var baseAssignValue = require('./_baseAssignValue'),
+    eq = require('./eq');
 
 /**
  * This function is like `assignValue` except that it doesn't assign
@@ -11,8 +12,8 @@ var eq = require('./eq');
  */
 function assignMergeValue(object, key, value) {
   if ((value !== undefined && !eq(object[key], value)) ||
-      (typeof key == 'number' && value === undefined && !(key in object))) {
+      (value === undefined && !(key in object))) {
-    object[key] = value;
+    baseAssignValue(object, key, value);
   }
 }
 

_assignValue.js

@@ -1,4 +1,5 @@
-var eq = require('./eq');
+var baseAssignValue = require('./_baseAssignValue'),
+    eq = require('./eq');
 
 /** Used for built-in method references. */
 var objectProto = Object.prototype;
@@ -8,7 +9,7 @@ var hasOwnProperty = objectProto.hasOwnProperty;
 
 /**
  * Assigns `value` to `key` of `object` if the existing value is not equivalent
- * using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+ * using [`SameValueZero`](http://ecma-international.org/ecma-262/7.0/#sec-samevaluezero)
  * for equality comparisons.
  *
  * @private
@@ -20,7 +21,7 @@ function assignValue(object, key, value) {
   var objValue = object[key];
   if (!(hasOwnProperty.call(object, key) && eq(objValue, value)) ||
       (value === undefined && !(key in object))) {
-    object[key] = value;
+    baseAssignValue(object, key, value);
   }
 }
 

_assocGet.js

@@ -1,16 +0,0 @@
-var assocIndexOf = require('./_assocIndexOf');
-
-/**
- * Gets the associative array value for `key`.
- *
- * @private
- * @param {Array} array The array to query.
- * @param {string} key The key of the value to get.
- * @returns {*} Returns the entry value.
- */
-function assocGet(array, key) {
-  var index = assocIndexOf(array, key);
-  return index < 0 ? undefined : array[index][1];
-}
-
-module.exports = assocGet;

_assocIndexOf.js

@@ -4,7 +4,7 @@ var eq = require('./eq');
  * Gets the index at which the `key` is found in `array` of key-value pairs.
  *
  * @private
- * @param {Array} array The array to search.
+ * @param {Array} array The array to inspect.
  * @param {*} key The key to search for.
  * @returns {number} Returns the index of the matched value, else `-1`.
  */

_assocSet.js

@@ -1,20 +0,0 @@
-var assocIndexOf = require('./_assocIndexOf');
-
-/**
- * Sets the associative array `key` to `value`.
- *
- * @private
- * @param {Array} array The array to modify.
- * @param {string} key The key of the value to set.
- * @param {*} value The value to set.
- */
-function assocSet(array, key, value) {
-  var index = assocIndexOf(array, key);
-  if (index < 0) {
-    array.push([key, value]);
-  } else {
-    array[index][1] = value;
-  }
-}
-
-module.exports = assocSet;

_baseAssignIn.js

@@ -0,0 +1,17 @@
+var copyObject = require('./_copyObject'),
+    keysIn = require('./keysIn');
+
+/**
+ * The base implementation of `_.assignIn` without support for multiple sources
+ * or `customizer` functions.
+ *
+ * @private
+ * @param {Object} object The destination object.
+ * @param {Object} source The source object.
+ * @returns {Object} Returns `object`.
+ */
+function baseAssignIn(object, source) {
+  return object && copyObject(source, keysIn(source), object);
+}
+
+module.exports = baseAssignIn;

_baseAssignValue.js

@@ -0,0 +1,25 @@
+var defineProperty = require('./_defineProperty');
+
+/**
+ * The base implementation of `assignValue` and `assignMergeValue` without
+ * value checks.
+ *
+ * @private
+ * @param {Object} object The object to modify.
+ * @param {string} key The key of the property to assign.
+ * @param {*} value The value to assign.
+ */
+function baseAssignValue(object, key, value) {
+  if (key == '__proto__' && defineProperty) {
+    defineProperty(object, key, {
+      'configurable': true,
+      'enumerable': true,
+      'value': value,
+      'writable': true
+    });
+  } else {
+    object[key] = value;
+  }
+}
+
+module.exports = baseAssignValue;

_baseAt.js

@@ -5,17 +5,17 @@ var get = require('./get');
  *
  * @private
  * @param {Object} object The object to iterate over.
- * @param {string[]} paths The property paths of elements to pick.
+ * @param {string[]} paths The property paths to pick.
- * @returns {Array} Returns the new array of picked elements.
+ * @returns {Array} Returns the picked elements.
  */
 function baseAt(object, paths) {
   var index = -1,
-      isNil = object == null,
       length = paths.length,
-      result = Array(length);
+      result = Array(length),
+      skip = object == null;
 
   while (++index < length) {
-    result[index] = isNil ? undefined : get(object, paths[index]);
+    result[index] = skip ? undefined : get(object, paths[index]);
   }
   return result;
 }

_baseCastKey.js

@@ -1,14 +0,0 @@
-var isSymbol = require('./isSymbol');
-
-/**
- * Casts `value` to a string if it's not a string or symbol.
- *
- * @private
- * @param {*} value The value to inspect.
- * @returns {string|symbol} Returns the cast key.
- */
-function baseCastKey(key) {
-  return (typeof key == 'string' || isSymbol(key)) ? key : (key + '');
-}
-
-module.exports = baseCastKey;

_baseCastPath.js

@@ -1,15 +0,0 @@
-var isArray = require('./isArray'),
-    stringToPath = require('./_stringToPath');
-
-/**
- * Casts `value` to a path array if it's not one.
- *
- * @private
- * @param {*} value The value to inspect.
- * @returns {Array} Returns the cast property path array.
- */
-function baseCastPath(value) {
-  return isArray(value) ? value : stringToPath(value);
-}
-
-module.exports = baseCastPath;

_baseClamp.js

@@ -1,5 +1,5 @@
 /**
- * The base implementation of `_.clamp` which doesn't coerce arguments to numbers.
+ * The base implementation of `_.clamp` which doesn't coerce arguments.
  *
  * @private
  * @param {number} number The number to clamp.

_baseClone.js

@@ -2,19 +2,29 @@ var Stack = require('./_Stack'),
     arrayEach = require('./_arrayEach'),
     assignValue = require('./_assignValue'),
     baseAssign = require('./_baseAssign'),
+    baseAssignIn = require('./_baseAssignIn'),
     cloneBuffer = require('./_cloneBuffer'),
     copyArray = require('./_copyArray'),
     copySymbols = require('./_copySymbols'),
+    copySymbolsIn = require('./_copySymbolsIn'),
     getAllKeys = require('./_getAllKeys'),
+    getAllKeysIn = require('./_getAllKeysIn'),
     getTag = require('./_getTag'),
     initCloneArray = require('./_initCloneArray'),
     initCloneByTag = require('./_initCloneByTag'),
     initCloneObject = require('./_initCloneObject'),
     isArray = require('./isArray'),
     isBuffer = require('./isBuffer'),
-    isHostObject = require('./_isHostObject'),
+    isMap = require('./isMap'),
     isObject = require('./isObject'),
-    keys = require('./keys');
+    isSet = require('./isSet'),
+    keys = require('./keys'),
+    keysIn = require('./keysIn');
+
+/** Used to compose bitmasks for cloning. */
+var CLONE_DEEP_FLAG = 1,
+    CLONE_FLAT_FLAG = 2,
+    CLONE_SYMBOLS_FLAG = 4;
 
 /** `Object#toString` result references. */
 var argsTag = '[object Arguments]',
@@ -67,16 +77,22 @@ cloneableTags[weakMapTag] = false;
  *
  * @private
  * @param {*} value The value to clone.
- * @param {boolean} [isDeep] Specify a deep clone.
+ * @param {boolean} bitmask The bitmask flags.
- * @param {boolean} [isFull] Specify a clone including symbols.
+ *  1 - Deep clone
+ *  2 - Flatten inherited properties
+ *  4 - Clone symbols
  * @param {Function} [customizer] The function to customize cloning.
  * @param {string} [key] The key of `value`.
  * @param {Object} [object] The parent object of `value`.
  * @param {Object} [stack] Tracks traversed objects and their clone counterparts.
  * @returns {*} Returns the cloned value.
  */
-function baseClone(value, isDeep, isFull, customizer, key, object, stack) {
+function baseClone(value, bitmask, customizer, key, object, stack) {
-  var result;
+  var result,
+      isDeep = bitmask & CLONE_DEEP_FLAG,
+      isFlat = bitmask & CLONE_FLAT_FLAG,
+      isFull = bitmask & CLONE_SYMBOLS_FLAG;
+
   if (customizer) {
     result = object ? customizer(value, key, object, stack) : customizer(value);
   }
@@ -100,18 +116,17 @@ function baseClone(value, isDeep, isFull, customizer, key, object, stack) {
       return cloneBuffer(value, isDeep);
     }
     if (tag == objectTag || tag == argsTag || (isFunc && !object)) {
-      if (isHostObject(value)) {
+      result = (isFlat || isFunc) ? {} : initCloneObject(value);
-        return object ? value : {};
-      }
-      result = initCloneObject(isFunc ? {} : value);
       if (!isDeep) {
-        return copySymbols(value, baseAssign(result, value));
+        return isFlat
+          ? copySymbolsIn(value, baseAssignIn(result, value))
+          : copySymbols(value, baseAssign(result, value));
       }
     } else {
       if (!cloneableTags[tag]) {
         return object ? value : {};
       }
-      result = initCloneByTag(value, tag, baseClone, isDeep);
+      result = initCloneByTag(value, tag, isDeep);
     }
   }
   // Check for circular references and return its corresponding clone.
@@ -122,16 +137,28 @@ function baseClone(value, isDeep, isFull, customizer, key, object, stack) {
   }
   stack.set(value, result);
 
-  if (!isArr) {
+  if (isSet(value)) {
-    var props = isFull ? getAllKeys(value) : keys(value);
+    value.forEach(function(subValue) {
+      result.add(baseClone(subValue, bitmask, customizer, subValue, value, stack));
+    });
+  } else if (isMap(value)) {
+    value.forEach(function(subValue, key) {
+      result.set(key, baseClone(subValue, bitmask, customizer, key, value, stack));
+    });
   }
-  // Recursively populate clone (susceptible to call stack limits).
+
+  var keysFunc = isFull
+    ? (isFlat ? getAllKeysIn : getAllKeys)
+    : (isFlat ? keysIn : keys);
+
+  var props = isArr ? undefined : keysFunc(value);
   arrayEach(props || value, function(subValue, key) {
     if (props) {
       key = subValue;
       subValue = value[key];
     }
-    assignValue(result, key, baseClone(subValue, isDeep, isFull, customizer, key, value, stack));
+    // Recursively populate clone (susceptible to call stack limits).
+    assignValue(result, key, baseClone(subValue, bitmask, customizer, key, value, stack));
   });
   return result;
 }

_baseConforms.js

@@ -1,32 +1,17 @@
-var keys = require('./keys');
+var baseConformsTo = require('./_baseConformsTo'),
+    keys = require('./keys');
 
 /**
  * The base implementation of `_.conforms` which doesn't clone `source`.
  *
  * @private
  * @param {Object} source The object of property predicates to conform to.
- * @returns {Function} Returns the new function.
+ * @returns {Function} Returns the new spec function.
  */
 function baseConforms(source) {
-  var props = keys(source),
+  var props = keys(source);
-      length = props.length;
-
   return function(object) {
-    if (object == null) {
+    return baseConformsTo(object, source, props);
-      return !length;
-    }
-    var index = length;
-    while (index--) {
-      var key = props[index],
-          predicate = source[key],
-          value = object[key];
-
-      if ((value === undefined &&
-          !(key in Object(object))) || !predicate(value)) {
-        return false;
-      }
-    }
-    return true;
   };
 }
 

_baseConformsTo.js

@@ -0,0 +1,27 @@
+/**
+ * The base implementation of `_.conformsTo` which accepts `props` to check.
+ *
+ * @private
+ * @param {Object} object The object to inspect.
+ * @param {Object} source The object of property predicates to conform to.
+ * @returns {boolean} Returns `true` if `object` conforms, else `false`.
+ */
+function baseConformsTo(object, source, props) {
+  var length = props.length;
+  if (object == null) {
+    return !length;
+  }
+  object = Object(object);
+  while (length--) {
+    var key = props[length],
+        predicate = source[key],
+        value = object[key];
+
+    if ((value === undefined && !(key in object)) || !predicate(value)) {
+      return false;
+    }
+  }
+  return true;
+}
+
+module.exports = baseConformsTo;

_baseCreate.js

@@ -8,11 +8,23 @@ var objectCreate = Object.create;
  * properties to the created object.
  *
  * @private
- * @param {Object} prototype The object to inherit from.
+ * @param {Object} proto The object to inherit from.
  * @returns {Object} Returns the new object.
  */
-function baseCreate(proto) {
+var baseCreate = (function() {
-  return isObject(proto) ? objectCreate(proto) : {};
+  function object() {}
-}
+  return function(proto) {
+    if (!isObject(proto)) {
+      return {};
+    }
+    if (objectCreate) {
+      return objectCreate(proto);
+    }
+    object.prototype = proto;
+    var result = new object;
+    object.prototype = undefined;
+    return result;
+  };
+}());
 
 module.exports = baseCreate;

_baseDelay.js

@@ -1,15 +1,15 @@
-/** Used as the `TypeError` message for "Functions" methods. */
+/** Error message constants. */
 var FUNC_ERROR_TEXT = 'Expected a function';
 
 /**
- * The base implementation of `_.delay` and `_.defer` which accepts an array
+ * The base implementation of `_.delay` and `_.defer` which accepts `args`
- * of `func` arguments.
+ * to provide to `func`.
  *
  * @private
  * @param {Function} func The function to delay.
  * @param {number} wait The number of milliseconds to delay invocation.
- * @param {Object} args The arguments to provide to `func`.
+ * @param {Array} args The arguments to provide to `func`.
- * @returns {number} Returns the timer id.
+ * @returns {number|Object} Returns the timer id or timeout object.
  */
 function baseDelay(func, wait, args) {
   if (typeof func != 'function') {

_baseDifference.js

@@ -45,8 +45,9 @@ function baseDifference(array, values, iteratee, comparator) {
   outer:
   while (++index < length) {
     var value = array[index],
-        computed = iteratee ? iteratee(value) : value;
+        computed = iteratee == null ? value : iteratee(value);
 
+    value = (comparator || value !== 0) ? value : 0;
     if (isCommon && computed === computed) {
       var valuesIndex = valuesLength;
       while (valuesIndex--) {

_baseExtremum.js

@@ -1,3 +1,5 @@
+var isSymbol = require('./isSymbol');
+
 /**
  * The base implementation of methods like `_.max` and `_.min` which accepts a
  * `comparator` to determine the extremum value.
@@ -17,7 +19,7 @@ function baseExtremum(array, iteratee, comparator) {
         current = iteratee(value);
 
     if (current != null && (computed === undefined
-          ? current === current
+          ? (current === current && !isSymbol(current))
           : comparator(current, computed)
         )) {
       var computed = current,

_baseFind.js

@@ -1,25 +0,0 @@
-/**
- * The base implementation of methods like `_.find` and `_.findKey`, without
- * support for iteratee shorthands, which iterates over `collection` using
- * `eachFunc`.
- *
- * @private
- * @param {Array|Object} collection The collection to search.
- * @param {Function} predicate The function invoked per iteration.
- * @param {Function} eachFunc The function to iterate over `collection`.
- * @param {boolean} [retKey] Specify returning the key of the found element
- *  instead of the element itself.
- * @returns {*} Returns the found element or its key, else `undefined`.
- */
-function baseFind(collection, predicate, eachFunc, retKey) {
-  var result;
-  eachFunc(collection, function(value, key, collection) {
-    if (predicate(value, key, collection)) {
-      result = retKey ? key : value;
-      return false;
-    }
-  });
-  return result;
-}
-
-module.exports = baseFind;

_baseFindIndex.js

@@ -3,14 +3,15 @@
  * support for iteratee shorthands.
  *
  * @private
- * @param {Array} array The array to search.
+ * @param {Array} array The array to inspect.
  * @param {Function} predicate The function invoked per iteration.
+ * @param {number} fromIndex The index to search from.
  * @param {boolean} [fromRight] Specify iterating from right to left.
  * @returns {number} Returns the index of the matched value, else `-1`.
  */
-function baseFindIndex(array, predicate, fromRight) {
+function baseFindIndex(array, predicate, fromIndex, fromRight) {
   var length = array.length,
-      index = fromRight ? length : -1;
+      index = fromIndex + (fromRight ? 1 : -1);
 
   while ((fromRight ? index-- : ++index < length)) {
     if (predicate(array[index], index, array)) {

_baseFindKey.js

@@ -0,0 +1,23 @@
+/**
+ * The base implementation of methods like `_.findKey` and `_.findLastKey`,
+ * without support for iteratee shorthands, which iterates over `collection`
+ * using `eachFunc`.
+ *
+ * @private
+ * @param {Array|Object} collection The collection to inspect.
+ * @param {Function} predicate The function invoked per iteration.
+ * @param {Function} eachFunc The function to iterate over `collection`.
+ * @returns {*} Returns the found element or its key, else `undefined`.
+ */
+function baseFindKey(collection, predicate, eachFunc) {
+  var result;
+  eachFunc(collection, function(value, key, collection) {
+    if (predicate(value, key, collection)) {
+      result = key;
+      return false;
+    }
+  });
+  return result;
+}
+
+module.exports = baseFindKey;

_baseFlatten.js

@@ -1,7 +1,5 @@
 var arrayPush = require('./_arrayPush'),
-    isArguments = require('./isArguments'),
+    isFlattenable = require('./_isFlattenable');
-    isArray = require('./isArray'),
-    isArrayLikeObject = require('./isArrayLikeObject');
 
 /**
  * The base implementation of `_.flatten` with support for restricting flattening.
@@ -9,23 +7,24 @@ var arrayPush = require('./_arrayPush'),
  * @private
  * @param {Array} array The array to flatten.
  * @param {number} depth The maximum recursion depth.
- * @param {boolean} [isStrict] Restrict flattening to arrays-like objects.
+ * @param {boolean} [predicate=isFlattenable] The function invoked per iteration.
+ * @param {boolean} [isStrict] Restrict to values that pass `predicate` checks.
  * @param {Array} [result=[]] The initial result value.
  * @returns {Array} Returns the new flattened array.
  */
-function baseFlatten(array, depth, isStrict, result) {
+function baseFlatten(array, depth, predicate, isStrict, result) {
-  result || (result = []);
-
   var index = -1,
       length = array.length;
 
+  predicate || (predicate = isFlattenable);
+  result || (result = []);
+
   while (++index < length) {
     var value = array[index];
-    if (depth > 0 && isArrayLikeObject(value) &&
+    if (depth > 0 && predicate(value)) {
-        (isStrict || isArray(value) || isArguments(value))) {
       if (depth > 1) {
         // Recursively flatten arrays (susceptible to call stack limits).
-        baseFlatten(value, depth - 1, isStrict, result);
+        baseFlatten(value, depth - 1, predicate, isStrict, result);
       } else {
         arrayPush(result, value);
       }

_baseFor.js

@@ -2,7 +2,7 @@ var createBaseFor = require('./_createBaseFor');
 
 /**
  * The base implementation of `baseForOwn` which iterates over `object`
- * properties returned by `keysFunc` invoking `iteratee` for each property.
+ * properties returned by `keysFunc` and invokes `iteratee` for each property.
  * Iteratee functions may exit iteration early by explicitly returning `false`.
  *
  * @private

_baseFunctions.js

@@ -8,7 +8,7 @@ var arrayFilter = require('./_arrayFilter'),
  * @private
  * @param {Object} object The object to inspect.
  * @param {Array} props The property names to filter.
- * @returns {Array} Returns the new array of filtered property names.
+ * @returns {Array} Returns the function names.
  */
 function baseFunctions(object, props) {
   return arrayFilter(props, function(key) {

_baseGet.js

@@ -1,5 +1,5 @@
-var baseCastPath = require('./_baseCastPath'),
+var castPath = require('./_castPath'),
-    isKey = require('./_isKey');
+    toKey = require('./_toKey');
 
 /**
  * The base implementation of `_.get` without support for default values.
@@ -10,13 +10,13 @@ var baseCastPath = require('./_baseCastPath'),
  * @returns {*} Returns the resolved value.
  */
 function baseGet(object, path) {
-  path = isKey(path, object) ? [path] : baseCastPath(path);
+  path = castPath(path, object);
 
   var index = 0,
       length = path.length;
 
   while (object != null && index < length) {
-    object = object[path[index++]];
+    object = object[toKey(path[index++])];
   }
   return (index && index == length) ? object : undefined;
 }

_baseGetAllKeys.js

@@ -14,9 +14,7 @@ var arrayPush = require('./_arrayPush'),
  */
 function baseGetAllKeys(object, keysFunc, symbolsFunc) {
   var result = keysFunc(object);
-  return isArray(object)
+  return isArray(object) ? result : arrayPush(result, symbolsFunc(object));
-    ? result
-    : arrayPush(result, symbolsFunc(object));
 }
 
 module.exports = baseGetAllKeys;

_baseGetTag.js

@@ -0,0 +1,28 @@
+var Symbol = require('./_Symbol'),
+    getRawTag = require('./_getRawTag'),
+    objectToString = require('./_objectToString');
+
+/** `Object#toString` result references. */
+var nullTag = '[object Null]',
+    undefinedTag = '[object Undefined]';
+
+/** Built-in value references. */
+var symToStringTag = Symbol ? Symbol.toStringTag : undefined;
+
+/**
+ * The base implementation of `getTag` without fallbacks for buggy environments.
+ *
+ * @private
+ * @param {*} value The value to query.
+ * @returns {string} Returns the `toStringTag`.
+ */
+function baseGetTag(value) {
+  if (value == null) {
+    return value === undefined ? undefinedTag : nullTag;
+  }
+  return (symToStringTag && symToStringTag in Object(value))
+    ? getRawTag(value)
+    : objectToString(value);
+}
+
+module.exports = baseGetTag;

_baseGt.js

@@ -0,0 +1,14 @@
+/**
+ * The base implementation of `_.gt` which doesn't coerce arguments.
+ *
+ * @private
+ * @param {*} value The value to compare.
+ * @param {*} other The other value to compare.
+ * @returns {boolean} Returns `true` if `value` is greater than `other`,
+ *  else `false`.
+ */
+function baseGt(value, other) {
+  return value > other;
+}
+
+module.exports = baseGt;

_baseHas.js

@@ -1,5 +1,3 @@
-var getPrototype = require('./_getPrototype');
-
 /** Used for built-in method references. */
 var objectProto = Object.prototype;
 
@@ -10,16 +8,12 @@ var hasOwnProperty = objectProto.hasOwnProperty;
  * The base implementation of `_.has` without support for deep paths.
  *
  * @private
- * @param {Object} object The object to query.
+ * @param {Object} [object] The object to query.
  * @param {Array|string} key The key to check.
  * @returns {boolean} Returns `true` if `key` exists, else `false`.
  */
 function baseHas(object, key) {
-  // Avoid a bug in IE 10-11 where objects with a [[Prototype]] of `null`,
+  return object != null && hasOwnProperty.call(object, key);
-  // that are composed entirely of index properties, return `false` for
-  // `hasOwnProperty` checks of them.
-  return hasOwnProperty.call(object, key) ||
-    (typeof object == 'object' && key in object && getPrototype(object) === null);
 }
 
 module.exports = baseHas;

_baseHasIn.js

@@ -2,12 +2,12 @@
  * The base implementation of `_.hasIn` without support for deep paths.
  *
  * @private
- * @param {Object} object The object to query.
+ * @param {Object} [object] The object to query.
  * @param {Array|string} key The key to check.
  * @returns {boolean} Returns `true` if `key` exists, else `false`.
  */
 function baseHasIn(object, key) {
-  return key in Object(object);
+  return object != null && key in Object(object);
 }
 
 module.exports = baseHasIn;

_baseInRange.js

@@ -3,7 +3,7 @@ var nativeMax = Math.max,
     nativeMin = Math.min;
 
 /**
- * The base implementation of `_.inRange` which doesn't coerce arguments to numbers.
+ * The base implementation of `_.inRange` which doesn't coerce arguments.
  *
  * @private
  * @param {number} number The number to check.

_baseIndexOf.js

@@ -1,27 +1,20 @@
-var indexOfNaN = require('./_indexOfNaN');
+var baseFindIndex = require('./_baseFindIndex'),
+    baseIsNaN = require('./_baseIsNaN'),
+    strictIndexOf = require('./_strictIndexOf');
 
 /**
  * The base implementation of `_.indexOf` without `fromIndex` bounds checks.
  *
  * @private
- * @param {Array} array The array to search.
+ * @param {Array} array The array to inspect.
  * @param {*} value The value to search for.
  * @param {number} fromIndex The index to search from.
  * @returns {number} Returns the index of the matched value, else `-1`.
  */
 function baseIndexOf(array, value, fromIndex) {
-  if (value !== value) {
+  return value === value
-    return indexOfNaN(array, fromIndex);
+    ? strictIndexOf(array, value, fromIndex)
-  }
+    : baseFindIndex(array, baseIsNaN, fromIndex);
-  var index = fromIndex - 1,
-      length = array.length;
-
-  while (++index < length) {
-    if (array[index] === value) {
-      return index;
-    }
-  }
-  return -1;
 }
 
 module.exports = baseIndexOf;

_baseIndexOfWith.js

@@ -2,7 +2,7 @@
  * This function is like `baseIndexOf` except that it accepts a comparator.
  *
  * @private
- * @param {Array} array The array to search.
+ * @param {Array} array The array to inspect.
  * @param {*} value The value to search for.
  * @param {number} fromIndex The index to search from.
  * @param {Function} comparator The comparator invoked per element.

_baseIntersection.js

@@ -47,6 +47,7 @@ function baseIntersection(arrays, iteratee, comparator) {
     var value = array[index],
         computed = iteratee ? iteratee(value) : value;
 
+    value = (comparator || value !== 0) ? value : 0;
     if (!(seen
           ? cacheHas(seen, computed)
           : includes(result, computed, comparator)

_baseInvoke.js

@@ -1,8 +1,8 @@
 var apply = require('./_apply'),
-    baseCastPath = require('./_baseCastPath'),
+    castPath = require('./_castPath'),
-    isKey = require('./_isKey'),
     last = require('./last'),
-    parent = require('./_parent');
+    parent = require('./_parent'),
+    toKey = require('./_toKey');
 
 /**
  * The base implementation of `_.invoke` without support for individual
@@ -15,12 +15,9 @@ var apply = require('./_apply'),
  * @returns {*} Returns the result of the invoked method.
  */
 function baseInvoke(object, path, args) {
-  if (!isKey(path, object)) {
+  path = castPath(path, object);
-    path = baseCastPath(path);
+  object = parent(object, path);
-    object = parent(object, path);
+  var func = object == null ? object : object[toKey(last(path))];
-    path = last(path);
-  }
-  var func = object == null ? object : object[path];
   return func == null ? undefined : apply(func, object, args);
 }
 

_baseIsArguments.js

@@ -0,0 +1,18 @@
+var baseGetTag = require('./_baseGetTag'),
+    isObjectLike = require('./isObjectLike');
+
+/** `Object#toString` result references. */
+var argsTag = '[object Arguments]';
+
+/**
+ * The base implementation of `_.isArguments`.
+ *
+ * @private
+ * @param {*} value The value to check.
+ * @returns {boolean} Returns `true` if `value` is an `arguments` object,
+ */
+function baseIsArguments(value) {
+  return isObjectLike(value) && baseGetTag(value) == argsTag;
+}
+
+module.exports = baseIsArguments;

_baseIsArrayBuffer.js

@@ -0,0 +1,17 @@
+var baseGetTag = require('./_baseGetTag'),
+    isObjectLike = require('./isObjectLike');
+
+var arrayBufferTag = '[object ArrayBuffer]';
+
+/**
+ * The base implementation of `_.isArrayBuffer` without Node.js optimizations.
+ *
+ * @private
+ * @param {*} value The value to check.
+ * @returns {boolean} Returns `true` if `value` is an array buffer, else `false`.
+ */
+function baseIsArrayBuffer(value) {
+  return isObjectLike(value) && baseGetTag(value) == arrayBufferTag;
+}
+
+module.exports = baseIsArrayBuffer;

_baseIsDate.js

@@ -0,0 +1,18 @@
+var baseGetTag = require('./_baseGetTag'),
+    isObjectLike = require('./isObjectLike');
+
+/** `Object#toString` result references. */
+var dateTag = '[object Date]';
+
+/**
+ * The base implementation of `_.isDate` without Node.js optimizations.
+ *
+ * @private
+ * @param {*} value The value to check.
+ * @returns {boolean} Returns `true` if `value` is a date object, else `false`.
+ */
+function baseIsDate(value) {
+  return isObjectLike(value) && baseGetTag(value) == dateTag;
+}
+
+module.exports = baseIsDate;

_baseIsEqual.js

@@ -1,5 +1,4 @@
 var baseIsEqualDeep = require('./_baseIsEqualDeep'),
-    isObject = require('./isObject'),
     isObjectLike = require('./isObjectLike');
 
 /**
@@ -9,22 +8,21 @@ var baseIsEqualDeep = require('./_baseIsEqualDeep'),
  * @private
  * @param {*} value The value to compare.
  * @param {*} other The other value to compare.
+ * @param {boolean} bitmask The bitmask flags.
+ *  1 - Unordered comparison
+ *  2 - Partial comparison
  * @param {Function} [customizer] The function to customize comparisons.
- * @param {boolean} [bitmask] The bitmask of comparison flags.
- *  The bitmask may be composed of the following flags:
- *     1 - Unordered comparison
- *     2 - Partial comparison
  * @param {Object} [stack] Tracks traversed `value` and `other` objects.
  * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
  */
-function baseIsEqual(value, other, customizer, bitmask, stack) {
+function baseIsEqual(value, other, bitmask, customizer, stack) {
   if (value === other) {
     return true;
   }
-  if (value == null || other == null || (!isObject(value) && !isObjectLike(other))) {
+  if (value == null || other == null || (!isObjectLike(value) && !isObjectLike(other))) {
     return value !== value && other !== other;
   }
-  return baseIsEqualDeep(value, other, baseIsEqual, customizer, bitmask, stack);
+  return baseIsEqualDeep(value, other, bitmask, customizer, baseIsEqual, stack);
 }
 
 module.exports = baseIsEqual;

_baseIsEqualDeep.js

@@ -4,11 +4,11 @@ var Stack = require('./_Stack'),
     equalObjects = require('./_equalObjects'),
     getTag = require('./_getTag'),
     isArray = require('./isArray'),
-    isHostObject = require('./_isHostObject'),
+    isBuffer = require('./isBuffer'),
     isTypedArray = require('./isTypedArray');
 
-/** Used to compose bitmasks for comparison styles. */
+/** Used to compose bitmasks for value comparisons. */
-var PARTIAL_COMPARE_FLAG = 2;
+var COMPARE_PARTIAL_FLAG = 1;
 
 /** `Object#toString` result references. */
 var argsTag = '[object Arguments]',
@@ -29,38 +29,39 @@ var hasOwnProperty = objectProto.hasOwnProperty;
  * @private
  * @param {Object} object The object to compare.
  * @param {Object} other The other object to compare.
+ * @param {number} bitmask The bitmask flags. See `baseIsEqual` for more details.
+ * @param {Function} customizer The function to customize comparisons.
  * @param {Function} equalFunc The function to determine equivalents of values.
- * @param {Function} [customizer] The function to customize comparisons.
- * @param {number} [bitmask] The bitmask of comparison flags. See `baseIsEqual`
- *  for more details.
  * @param {Object} [stack] Tracks traversed `object` and `other` objects.
  * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
  */
-function baseIsEqualDeep(object, other, equalFunc, customizer, bitmask, stack) {
+function baseIsEqualDeep(object, other, bitmask, customizer, equalFunc, stack) {
   var objIsArr = isArray(object),
       othIsArr = isArray(other),
-      objTag = arrayTag,
+      objTag = objIsArr ? arrayTag : getTag(object),
-      othTag = arrayTag;
+      othTag = othIsArr ? arrayTag : getTag(other);
 
-  if (!objIsArr) {
+  objTag = objTag == argsTag ? objectTag : objTag;
-    objTag = getTag(object);
+  othTag = othTag == argsTag ? objectTag : othTag;
-    objTag = objTag == argsTag ? objectTag : objTag;
+
-  }
+  var objIsObj = objTag == objectTag,
-  if (!othIsArr) {
+      othIsObj = othTag == objectTag,
-    othTag = getTag(other);
-    othTag = othTag == argsTag ? objectTag : othTag;
-  }
-  var objIsObj = objTag == objectTag && !isHostObject(object),
-      othIsObj = othTag == objectTag && !isHostObject(other),
       isSameTag = objTag == othTag;
 
+  if (isSameTag && isBuffer(object)) {
+    if (!isBuffer(other)) {
+      return false;
+    }
+    objIsArr = true;
+    objIsObj = false;
+  }
   if (isSameTag && !objIsObj) {
     stack || (stack = new Stack);
     return (objIsArr || isTypedArray(object))
-      ? equalArrays(object, other, equalFunc, customizer, bitmask, stack)
+      ? equalArrays(object, other, bitmask, customizer, equalFunc, stack)
-      : equalByTag(object, other, objTag, equalFunc, customizer, bitmask, stack);
+      : equalByTag(object, other, objTag, bitmask, customizer, equalFunc, stack);
   }
-  if (!(bitmask & PARTIAL_COMPARE_FLAG)) {
+  if (!(bitmask & COMPARE_PARTIAL_FLAG)) {
     var objIsWrapped = objIsObj && hasOwnProperty.call(object, '__wrapped__'),
         othIsWrapped = othIsObj && hasOwnProperty.call(other, '__wrapped__');
 
@@ -69,14 +70,14 @@ function baseIsEqualDeep(object, other, equalFunc, customizer, bitmask, stack) {
           othUnwrapped = othIsWrapped ? other.value() : other;
 
       stack || (stack = new Stack);
-      return equalFunc(objUnwrapped, othUnwrapped, customizer, bitmask, stack);
+      return equalFunc(objUnwrapped, othUnwrapped, bitmask, customizer, stack);
     }
   }
   if (!isSameTag) {
     return false;
   }
   stack || (stack = new Stack);
-  return equalObjects(object, other, equalFunc, customizer, bitmask, stack);
+  return equalObjects(object, other, bitmask, customizer, equalFunc, stack);
 }
 
 module.exports = baseIsEqualDeep;

_baseIsMap.js

@@ -0,0 +1,18 @@
+var getTag = require('./_getTag'),
+    isObjectLike = require('./isObjectLike');
+
+/** `Object#toString` result references. */
+var mapTag = '[object Map]';
+
+/**
+ * The base implementation of `_.isMap` without Node.js optimizations.
+ *
+ * @private
+ * @param {*} value The value to check.
+ * @returns {boolean} Returns `true` if `value` is a map, else `false`.
+ */
+function baseIsMap(value) {
+  return isObjectLike(value) && getTag(value) == mapTag;
+}
+
+module.exports = baseIsMap;

_baseIsMatch.js

@@ -1,9 +1,9 @@
 var Stack = require('./_Stack'),
     baseIsEqual = require('./_baseIsEqual');
 
-/** Used to compose bitmasks for comparison styles. */
+/** Used to compose bitmasks for value comparisons. */
-var UNORDERED_COMPARE_FLAG = 1,
+var COMPARE_PARTIAL_FLAG = 1,
-    PARTIAL_COMPARE_FLAG = 2;
+    COMPARE_UNORDERED_FLAG = 2;
 
 /**
  * The base implementation of `_.isMatch` without support for iteratee shorthands.
@@ -49,7 +49,7 @@ function baseIsMatch(object, source, matchData, customizer) {
         var result = customizer(objValue, srcValue, key, object, source, stack);
       }
       if (!(result === undefined
-            ? baseIsEqual(srcValue, objValue, customizer, UNORDERED_COMPARE_FLAG | PARTIAL_COMPARE_FLAG, stack)
+            ? baseIsEqual(srcValue, objValue, COMPARE_PARTIAL_FLAG | COMPARE_UNORDERED_FLAG, customizer, stack)
             : result
           )) {
         return false;

_baseIsNaN.js

@@ -0,0 +1,12 @@
+/**
+ * The base implementation of `_.isNaN` without support for number objects.
+ *
+ * @private
+ * @param {*} value The value to check.
+ * @returns {boolean} Returns `true` if `value` is `NaN`, else `false`.
+ */
+function baseIsNaN(value) {
+  return value !== value;
+}
+
+module.exports = baseIsNaN;

_baseIsNative.js

@@ -0,0 +1,47 @@
+var isFunction = require('./isFunction'),
+    isMasked = require('./_isMasked'),
+    isObject = require('./isObject'),
+    toSource = require('./_toSource');
+
+/**
+ * Used to match `RegExp`
+ * [syntax characters](http://ecma-international.org/ecma-262/7.0/#sec-patterns).
+ */
+var reRegExpChar = /[\\^$.*+?()[\]{}|]/g;
+
+/** Used to detect host constructors (Safari). */
+var reIsHostCtor = /^\[object .+?Constructor\]$/;
+
+/** Used for built-in method references. */
+var funcProto = Function.prototype,
+    objectProto = Object.prototype;
+
+/** Used to resolve the decompiled source of functions. */
+var funcToString = funcProto.toString;
+
+/** Used to check objects for own properties. */
+var hasOwnProperty = objectProto.hasOwnProperty;
+
+/** Used to detect if a method is native. */
+var reIsNative = RegExp('^' +
+  funcToString.call(hasOwnProperty).replace(reRegExpChar, '\\$&')
+  .replace(/hasOwnProperty|(function).*?(?=\\\()| for .+?(?=\\\])/g, '$1.*?') + '$'
+);
+
+/**
+ * The base implementation of `_.isNative` without bad shim checks.
+ *
+ * @private
+ * @param {*} value The value to check.
+ * @returns {boolean} Returns `true` if `value` is a native function,
+ *  else `false`.
+ */
+function baseIsNative(value) {
+  if (!isObject(value) || isMasked(value)) {
+    return false;
+  }
+  var pattern = isFunction(value) ? reIsNative : reIsHostCtor;
+  return pattern.test(toSource(value));
+}
+
+module.exports = baseIsNative;

_baseIsRegExp.js

@@ -0,0 +1,18 @@
+var baseGetTag = require('./_baseGetTag'),
+    isObjectLike = require('./isObjectLike');
+
+/** `Object#toString` result references. */
+var regexpTag = '[object RegExp]';
+
+/**
+ * The base implementation of `_.isRegExp` without Node.js optimizations.
+ *
+ * @private
+ * @param {*} value The value to check.
+ * @returns {boolean} Returns `true` if `value` is a regexp, else `false`.
+ */
+function baseIsRegExp(value) {
+  return isObjectLike(value) && baseGetTag(value) == regexpTag;
+}
+
+module.exports = baseIsRegExp;

_baseIsSet.js

@@ -0,0 +1,18 @@
+var getTag = require('./_getTag'),
+    isObjectLike = require('./isObjectLike');
+
+/** `Object#toString` result references. */
+var setTag = '[object Set]';
+
+/**
+ * The base implementation of `_.isSet` without Node.js optimizations.
+ *
+ * @private
+ * @param {*} value The value to check.
+ * @returns {boolean} Returns `true` if `value` is a set, else `false`.
+ */
+function baseIsSet(value) {
+  return isObjectLike(value) && getTag(value) == setTag;
+}
+
+module.exports = baseIsSet;

_baseIsTypedArray.js

@@ -0,0 +1,60 @@
+var baseGetTag = require('./_baseGetTag'),
+    isLength = require('./isLength'),
+    isObjectLike = require('./isObjectLike');
+
+/** `Object#toString` result references. */
+var argsTag = '[object Arguments]',
+    arrayTag = '[object Array]',
+    boolTag = '[object Boolean]',
+    dateTag = '[object Date]',
+    errorTag = '[object Error]',
+    funcTag = '[object Function]',
+    mapTag = '[object Map]',
+    numberTag = '[object Number]',
+    objectTag = '[object Object]',
+    regexpTag = '[object RegExp]',
+    setTag = '[object Set]',
+    stringTag = '[object String]',
+    weakMapTag = '[object WeakMap]';
+
+var arrayBufferTag = '[object ArrayBuffer]',
+    dataViewTag = '[object DataView]',
+    float32Tag = '[object Float32Array]',
+    float64Tag = '[object Float64Array]',
+    int8Tag = '[object Int8Array]',
+    int16Tag = '[object Int16Array]',
+    int32Tag = '[object Int32Array]',
+    uint8Tag = '[object Uint8Array]',
+    uint8ClampedTag = '[object Uint8ClampedArray]',
+    uint16Tag = '[object Uint16Array]',
+    uint32Tag = '[object Uint32Array]';
+
+/** Used to identify `toStringTag` values of typed arrays. */
+var typedArrayTags = {};
+typedArrayTags[float32Tag] = typedArrayTags[float64Tag] =
+typedArrayTags[int8Tag] = typedArrayTags[int16Tag] =
+typedArrayTags[int32Tag] = typedArrayTags[uint8Tag] =
+typedArrayTags[uint8ClampedTag] = typedArrayTags[uint16Tag] =
+typedArrayTags[uint32Tag] = true;
+typedArrayTags[argsTag] = typedArrayTags[arrayTag] =
+typedArrayTags[arrayBufferTag] = typedArrayTags[boolTag] =
+typedArrayTags[dataViewTag] = typedArrayTags[dateTag] =
+typedArrayTags[errorTag] = typedArrayTags[funcTag] =
+typedArrayTags[mapTag] = typedArrayTags[numberTag] =
+typedArrayTags[objectTag] = typedArrayTags[regexpTag] =
+typedArrayTags[setTag] = typedArrayTags[stringTag] =
+typedArrayTags[weakMapTag] = false;
+
+/**
+ * The base implementation of `_.isTypedArray` without Node.js optimizations.
+ *
+ * @private
+ * @param {*} value The value to check.
+ * @returns {boolean} Returns `true` if `value` is a typed array, else `false`.
+ */
+function baseIsTypedArray(value) {
+  return isObjectLike(value) &&
+    isLength(value.length) && !!typedArrayTags[baseGetTag(value)];
+}
+
+module.exports = baseIsTypedArray;

_baseKeys.js

@@ -1,16 +1,30 @@
-/* Built-in method references for those with the same name as other `lodash` methods. */
+var isPrototype = require('./_isPrototype'),
-var nativeKeys = Object.keys;
+    nativeKeys = require('./_nativeKeys');
+
+/** Used for built-in method references. */
+var objectProto = Object.prototype;
+
+/** Used to check objects for own properties. */
+var hasOwnProperty = objectProto.hasOwnProperty;
 
 /**
- * The base implementation of `_.keys` which doesn't skip the constructor
+ * The base implementation of `_.keys` which doesn't treat sparse arrays as dense.
- * property of prototypes or treat sparse arrays as dense.
  *
  * @private
  * @param {Object} object The object to query.
  * @returns {Array} Returns the array of property names.
  */
 function baseKeys(object) {
-  return nativeKeys(Object(object));
+  if (!isPrototype(object)) {
+    return nativeKeys(object);
+  }
+  var result = [];
+  for (var key in Object(object)) {
+    if (hasOwnProperty.call(object, key) && key != 'constructor') {
+      result.push(key);
+    }
+  }
+  return result;
 }
 
 module.exports = baseKeys;

_baseKeysIn.js

@@ -1,36 +1,33 @@
-var Reflect = require('./_Reflect'),
+var isObject = require('./isObject'),
-    iteratorToArray = require('./_iteratorToArray');
+    isPrototype = require('./_isPrototype'),
+    nativeKeysIn = require('./_nativeKeysIn');
 
 /** Used for built-in method references. */
 var objectProto = Object.prototype;
 
-/** Built-in value references. */
+/** Used to check objects for own properties. */
-var enumerate = Reflect ? Reflect.enumerate : undefined,
+var hasOwnProperty = objectProto.hasOwnProperty;
-    propertyIsEnumerable = objectProto.propertyIsEnumerable;
 
 /**
- * The base implementation of `_.keysIn` which doesn't skip the constructor
+ * The base implementation of `_.keysIn` which doesn't treat sparse arrays as dense.
- * property of prototypes or treat sparse arrays as dense.
  *
  * @private
  * @param {Object} object The object to query.
  * @returns {Array} Returns the array of property names.
  */
 function baseKeysIn(object) {
-  object = object == null ? object : Object(object);
+  if (!isObject(object)) {
+    return nativeKeysIn(object);
+  }
+  var isProto = isPrototype(object),
+      result = [];
 
-  var result = [];
   for (var key in object) {
-    result.push(key);
+    if (!(key == 'constructor' && (isProto || !hasOwnProperty.call(object, key)))) {
+      result.push(key);
+    }
   }
   return result;
 }
 
-// Fallback for IE < 9 with es6-shim.
-if (enumerate && !propertyIsEnumerable.call({ 'valueOf': 1 }, 'valueOf')) {
-  baseKeysIn = function(object) {
-    return iteratorToArray(enumerate(object));
-  };
-}
-
 module.exports = baseKeysIn;

_baseLt.js

@@ -0,0 +1,14 @@
+/**
+ * The base implementation of `_.lt` which doesn't coerce arguments.
+ *
+ * @private
+ * @param {*} value The value to compare.
+ * @param {*} other The other value to compare.
+ * @returns {boolean} Returns `true` if `value` is less than `other`,
+ *  else `false`.
+ */
+function baseLt(value, other) {
+  return value < other;
+}
+
+module.exports = baseLt;

_baseMatches.js

@@ -7,7 +7,7 @@ var baseIsMatch = require('./_baseIsMatch'),
  *
  * @private
  * @param {Object} source The object of property values to match.
- * @returns {Function} Returns the new function.
+ * @returns {Function} Returns the new spec function.
  */
 function baseMatches(source) {
   var matchData = getMatchData(source);

_baseMatchesProperty.js

@@ -3,11 +3,12 @@ var baseIsEqual = require('./_baseIsEqual'),
     hasIn = require('./hasIn'),
     isKey = require('./_isKey'),
     isStrictComparable = require('./_isStrictComparable'),
-    matchesStrictComparable = require('./_matchesStrictComparable');
+    matchesStrictComparable = require('./_matchesStrictComparable'),
+    toKey = require('./_toKey');
 
-/** Used to compose bitmasks for comparison styles. */
+/** Used to compose bitmasks for value comparisons. */
-var UNORDERED_COMPARE_FLAG = 1,
+var COMPARE_PARTIAL_FLAG = 1,
-    PARTIAL_COMPARE_FLAG = 2;
+    COMPARE_UNORDERED_FLAG = 2;
 
 /**
  * The base implementation of `_.matchesProperty` which doesn't clone `srcValue`.
@@ -15,17 +16,17 @@ var UNORDERED_COMPARE_FLAG = 1,
  * @private
  * @param {string} path The path of the property to get.
  * @param {*} srcValue The value to match.
- * @returns {Function} Returns the new function.
+ * @returns {Function} Returns the new spec function.
  */
 function baseMatchesProperty(path, srcValue) {
   if (isKey(path) && isStrictComparable(srcValue)) {
-    return matchesStrictComparable(path, srcValue);
+    return matchesStrictComparable(toKey(path), srcValue);
   }
   return function(object) {
     var objValue = get(object, path);
     return (objValue === undefined && objValue === srcValue)
       ? hasIn(object, path)
-      : baseIsEqual(srcValue, objValue, undefined, UNORDERED_COMPARE_FLAG | PARTIAL_COMPARE_FLAG);
+      : baseIsEqual(srcValue, objValue, COMPARE_PARTIAL_FLAG | COMPARE_UNORDERED_FLAG);
   };
 }
 

_baseMean.js

@@ -13,7 +13,7 @@ var NAN = 0 / 0;
  * @returns {number} Returns the mean.
  */
 function baseMean(array, iteratee) {
-  var length = array ? array.length : 0;
+  var length = array == null ? 0 : array.length;
   return length ? (baseSum(array, iteratee) / length) : NAN;
 }
 

_baseMerge.js

@@ -1,11 +1,10 @@
 var Stack = require('./_Stack'),
-    arrayEach = require('./_arrayEach'),
     assignMergeValue = require('./_assignMergeValue'),
+    baseFor = require('./_baseFor'),
     baseMergeDeep = require('./_baseMergeDeep'),
-    isArray = require('./isArray'),
     isObject = require('./isObject'),
-    isTypedArray = require('./isTypedArray'),
+    keysIn = require('./keysIn'),
-    keysIn = require('./keysIn');
+    safeGet = require('./_safeGet');
 
 /**
  * The base implementation of `_.merge` without support for multiple sources.
@@ -22,21 +21,14 @@ function baseMerge(object, source, srcIndex, customizer, stack) {
   if (object === source) {
     return;
   }
-  if (!(isArray(source) || isTypedArray(source))) {
+  baseFor(source, function(srcValue, key) {
-    var props = keysIn(source);
+    stack || (stack = new Stack);
-  }
-  arrayEach(props || source, function(srcValue, key) {
-    if (props) {
-      key = srcValue;
-      srcValue = source[key];
-    }
     if (isObject(srcValue)) {
-      stack || (stack = new Stack);
       baseMergeDeep(object, source, key, srcIndex, baseMerge, customizer, stack);
     }
     else {
       var newValue = customizer
-        ? customizer(object[key], srcValue, (key + ''), object, source, stack)
+        ? customizer(safeGet(object, key), srcValue, (key + ''), object, source, stack)
         : undefined;
 
       if (newValue === undefined) {
@@ -44,7 +36,7 @@ function baseMerge(object, source, srcIndex, customizer, stack) {
       }
       assignMergeValue(object, key, newValue);
     }
-  });
+  }, keysIn);
 }
 
 module.exports = baseMerge;

_baseMergeDeep.js

@@ -1,13 +1,17 @@
 var assignMergeValue = require('./_assignMergeValue'),
-    baseClone = require('./_baseClone'),
+    cloneBuffer = require('./_cloneBuffer'),
+    cloneTypedArray = require('./_cloneTypedArray'),
     copyArray = require('./_copyArray'),
+    initCloneObject = require('./_initCloneObject'),
     isArguments = require('./isArguments'),
     isArray = require('./isArray'),
     isArrayLikeObject = require('./isArrayLikeObject'),
+    isBuffer = require('./isBuffer'),
     isFunction = require('./isFunction'),
     isObject = require('./isObject'),
     isPlainObject = require('./isPlainObject'),
     isTypedArray = require('./isTypedArray'),
+    safeGet = require('./_safeGet'),
     toPlainObject = require('./toPlainObject');
 
 /**
@@ -26,8 +30,8 @@ var assignMergeValue = require('./_assignMergeValue'),
  *  counterparts.
  */
 function baseMergeDeep(object, source, key, srcIndex, mergeFunc, customizer, stack) {
-  var objValue = object[key],
+  var objValue = safeGet(object, key),
-      srcValue = source[key],
+      srcValue = safeGet(source, key),
       stacked = stack.get(srcValue);
 
   if (stacked) {
@@ -41,42 +45,49 @@ function baseMergeDeep(object, source, key, srcIndex, mergeFunc, customizer, sta
   var isCommon = newValue === undefined;
 
   if (isCommon) {
+    var isArr = isArray(srcValue),
+        isBuff = !isArr && isBuffer(srcValue),
+        isTyped = !isArr && !isBuff && isTypedArray(srcValue);
+
     newValue = srcValue;
-    if (isArray(srcValue) || isTypedArray(srcValue)) {
+    if (isArr || isBuff || isTyped) {
       if (isArray(objValue)) {
         newValue = objValue;
       }
       else if (isArrayLikeObject(objValue)) {
         newValue = copyArray(objValue);
       }
-      else {
+      else if (isBuff) {
         isCommon = false;
-        newValue = baseClone(srcValue, true);
+        newValue = cloneBuffer(srcValue, true);
+      }
+      else if (isTyped) {
+        isCommon = false;
+        newValue = cloneTypedArray(srcValue, true);
+      }
+      else {
+        newValue = [];
       }
     }
     else if (isPlainObject(srcValue) || isArguments(srcValue)) {
+      newValue = objValue;
       if (isArguments(objValue)) {
         newValue = toPlainObject(objValue);
       }
-      else if (!isObject(objValue) || (srcIndex && isFunction(objValue))) {
+      else if (!isObject(objValue) || isFunction(objValue)) {
-        isCommon = false;
+        newValue = initCloneObject(srcValue);
-        newValue = baseClone(srcValue, true);
-      }
-      else {
-        newValue = objValue;
       }
     }
     else {
       isCommon = false;
     }
   }
-  stack.set(srcValue, newValue);
-
   if (isCommon) {
     // Recursively merge objects and arrays (susceptible to call stack limits).
+    stack.set(srcValue, newValue);
     mergeFunc(newValue, srcValue, srcIndex, customizer, stack);
+    stack['delete'](srcValue);
   }
-  stack['delete'](srcValue);
   assignMergeValue(object, key, newValue);
 }
 

_baseNth.js

@@ -0,0 +1,20 @@
+var isIndex = require('./_isIndex');
+
+/**
+ * The base implementation of `_.nth` which doesn't coerce arguments.
+ *
+ * @private
+ * @param {Array} array The array to query.
+ * @param {number} n The index of the element to return.
+ * @returns {*} Returns the nth element of `array`.
+ */
+function baseNth(array, n) {
+  var length = array.length;
+  if (!length) {
+    return;
+  }
+  n += n < 0 ? length : 0;
+  return isIndex(n, length) ? array[n] : undefined;
+}
+
+module.exports = baseNth;

_baseOrderBy.js

@@ -1,9 +1,12 @@
 var arrayMap = require('./_arrayMap'),
+    baseGet = require('./_baseGet'),
     baseIteratee = require('./_baseIteratee'),
     baseMap = require('./_baseMap'),
     baseSortBy = require('./_baseSortBy'),
+    baseUnary = require('./_baseUnary'),
     compareMultiple = require('./_compareMultiple'),
-    identity = require('./identity');
+    identity = require('./identity'),
+    isArray = require('./isArray');
 
 /**
  * The base implementation of `_.orderBy` without param guards.
@@ -15,8 +18,21 @@ var arrayMap = require('./_arrayMap'),
  * @returns {Array} Returns the new sorted array.
  */
 function baseOrderBy(collection, iteratees, orders) {
+  if (iteratees.length) {
+    iteratees = arrayMap(iteratees, function(iteratee) {
+      if (isArray(iteratee)) {
+        return function(value) {
+          return baseGet(value, iteratee.length === 1 ? iteratee[0] : iteratee);
+        }
+      }
+      return iteratee;
+    });
+  } else {
+    iteratees = [identity];
+  }
+
   var index = -1;
-  iteratees = arrayMap(iteratees.length ? iteratees : [identity], baseIteratee);
+  iteratees = arrayMap(iteratees, baseUnary(baseIteratee));
 
   var result = baseMap(collection, function(value, key, collection) {
     var criteria = arrayMap(iteratees, function(iteratee) {

_basePick.js

@@ -1,4 +1,5 @@
-var arrayReduce = require('./_arrayReduce');
+var basePickBy = require('./_basePickBy'),
+    hasIn = require('./hasIn');
 
 /**
  * The base implementation of `_.pick` without support for individual
@@ -6,17 +7,13 @@ var arrayReduce = require('./_arrayReduce');
  *
  * @private
  * @param {Object} object The source object.
- * @param {string[]} props The property identifiers to pick.
+ * @param {string[]} paths The property paths to pick.
  * @returns {Object} Returns the new object.
  */
-function basePick(object, props) {
+function basePick(object, paths) {
-  object = Object(object);
+  return basePickBy(object, paths, function(value, path) {
-  return arrayReduce(props, function(result, key) {
+    return hasIn(object, path);
-    if (key in object) {
+  });
-      result[key] = object[key];
-    }
-    return result;
-  }, {});
 }
 
 module.exports = basePick;

_basePickBy.js

@@ -1,25 +1,27 @@
-var getAllKeysIn = require('./_getAllKeysIn');
+var baseGet = require('./_baseGet'),
+    baseSet = require('./_baseSet'),
+    castPath = require('./_castPath');
 
 /**
  * The base implementation of  `_.pickBy` without support for iteratee shorthands.
  *
  * @private
  * @param {Object} object The source object.
+ * @param {string[]} paths The property paths to pick.
  * @param {Function} predicate The function invoked per property.
  * @returns {Object} Returns the new object.
  */
-function basePickBy(object, predicate) {
+function basePickBy(object, paths, predicate) {
   var index = -1,
-      props = getAllKeysIn(object),
+      length = paths.length,
-      length = props.length,
       result = {};
 
   while (++index < length) {
-    var key = props[index],
+    var path = paths[index],
-        value = object[key];
+        value = baseGet(object, path);
 
-    if (predicate(value, key)) {
+    if (predicate(value, path)) {
-      result[key] = value;
+      baseSet(result, castPath(path, object), value);
     }
   }
   return result;

_baseProperty.js

@@ -3,7 +3,7 @@
  *
  * @private
  * @param {string} key The key of the property to get.
- * @returns {Function} Returns the new function.
+ * @returns {Function} Returns the new accessor function.
  */
 function baseProperty(key) {
   return function(object) {

_basePropertyDeep.js

@@ -5,7 +5,7 @@ var baseGet = require('./_baseGet');
  *
  * @private
  * @param {Array|string} path The path of the property to get.
- * @returns {Function} Returns the new function.
+ * @returns {Function} Returns the new accessor function.
  */
 function basePropertyDeep(path) {
   return function(object) {

_basePropertyOf.js

@@ -0,0 +1,14 @@
+/**
+ * The base implementation of `_.propertyOf` without support for deep paths.
+ *
+ * @private
+ * @param {Object} object The object to query.
+ * @returns {Function} Returns the new accessor function.
+ */
+function basePropertyOf(object) {
+  return function(key) {
+    return object == null ? undefined : object[key];
+  };
+}
+
+module.exports = basePropertyOf;

_basePullAll.js

@@ -1,7 +1,8 @@
 var arrayMap = require('./_arrayMap'),
     baseIndexOf = require('./_baseIndexOf'),
     baseIndexOfWith = require('./_baseIndexOfWith'),
-    baseUnary = require('./_baseUnary');
+    baseUnary = require('./_baseUnary'),
+    copyArray = require('./_copyArray');
 
 /** Used for built-in method references. */
 var arrayProto = Array.prototype;
@@ -26,6 +27,9 @@ function basePullAll(array, values, iteratee, comparator) {
       length = values.length,
       seen = array;
 
+  if (array === values) {
+    values = copyArray(values);
+  }
   if (iteratee) {
     seen = arrayMap(array, baseUnary(iteratee));
   }

_basePullAt.js

@@ -1,8 +1,5 @@
-var baseCastPath = require('./_baseCastPath'),
+var baseUnset = require('./_baseUnset'),
-    isIndex = require('./_isIndex'),
+    isIndex = require('./_isIndex');
-    isKey = require('./_isKey'),
-    last = require('./last'),
-    parent = require('./_parent');
 
 /** Used for built-in method references. */
 var arrayProto = Array.prototype;
@@ -25,21 +22,12 @@ function basePullAt(array, indexes) {
 
   while (length--) {
     var index = indexes[length];
-    if (lastIndex == length || index != previous) {
+    if (length == lastIndex || index !== previous) {
       var previous = index;
       if (isIndex(index)) {
         splice.call(array, index, 1);
-      }
+      } else {
-      else if (!isKey(index, array)) {
+        baseUnset(array, index);
-        var path = baseCastPath(index),
-            object = parent(array, path);
-
-        if (object != null) {
-          delete object[last(path)];
-        }
-      }
-      else {
-        delete array[index];
       }
     }
   }

_baseRange.js

@@ -4,14 +4,14 @@ var nativeCeil = Math.ceil,
 
 /**
  * The base implementation of `_.range` and `_.rangeRight` which doesn't
- * coerce arguments to numbers.
+ * coerce arguments.
  *
  * @private
  * @param {number} start The start of the range.
  * @param {number} end The end of the range.
  * @param {number} step The value to increment or decrement by.
  * @param {boolean} [fromRight] Specify iterating from right to left.
- * @returns {Array} Returns the new array of numbers.
+ * @returns {Array} Returns the range of numbers.
  */
 function baseRange(start, end, step, fromRight) {
   var index = -1,

_baseRest.js

@@ -0,0 +1,17 @@
+var identity = require('./identity'),
+    overRest = require('./_overRest'),
+    setToString = require('./_setToString');
+
+/**
+ * The base implementation of `_.rest` which doesn't validate or coerce arguments.
+ *
+ * @private
+ * @param {Function} func The function to apply a rest parameter to.
+ * @param {number} [start=func.length-1] The start position of the rest parameter.
+ * @returns {Function} Returns the new function.
+ */
+function baseRest(func, start) {
+  return setToString(overRest(func, start, identity), func + '');
+}
+
+module.exports = baseRest;

_baseSample.js

@@ -0,0 +1,15 @@
+var arraySample = require('./_arraySample'),
+    values = require('./values');
+
+/**
+ * The base implementation of `_.sample`.
+ *
+ * @private
+ * @param {Array|Object} collection The collection to sample.
+ * @returns {*} Returns the random element.
+ */
+function baseSample(collection) {
+  return arraySample(values(collection));
+}
+
+module.exports = baseSample;

_baseSampleSize.js

@@ -0,0 +1,18 @@
+var baseClamp = require('./_baseClamp'),
+    shuffleSelf = require('./_shuffleSelf'),
+    values = require('./values');
+
+/**
+ * The base implementation of `_.sampleSize` without param guards.
+ *
+ * @private
+ * @param {Array|Object} collection The collection to sample.
+ * @param {number} n The number of elements to sample.
+ * @returns {Array} Returns the random elements.
+ */
+function baseSampleSize(collection, n) {
+  var array = values(collection);
+  return shuffleSelf(array, baseClamp(n, 0, array.length));
+}
+
+module.exports = baseSampleSize;

_baseSet.js

@@ -1,21 +1,24 @@
 var assignValue = require('./_assignValue'),
-    baseCastPath = require('./_baseCastPath'),
+    castPath = require('./_castPath'),
     isIndex = require('./_isIndex'),
-    isKey = require('./_isKey'),
+    isObject = require('./isObject'),
-    isObject = require('./isObject');
+    toKey = require('./_toKey');
 
 /**
  * The base implementation of `_.set`.
  *
  * @private
- * @param {Object} object The object to query.
+ * @param {Object} object The object to modify.
  * @param {Array|string} path The path of the property to set.
  * @param {*} value The value to set.
  * @param {Function} [customizer] The function to customize path creation.
  * @returns {Object} Returns `object`.
  */
 function baseSet(object, path, value, customizer) {
-  path = isKey(path, object) ? [path] : baseCastPath(path);
+  if (!isObject(object)) {
+    return object;
+  }
+  path = castPath(path, object);
 
   var index = -1,
       length = path.length,
@@ -23,20 +26,23 @@ function baseSet(object, path, value, customizer) {
       nested = object;
 
   while (nested != null && ++index < length) {
-    var key = path[index];
+    var key = toKey(path[index]),
-    if (isObject(nested)) {
+        newValue = value;
-      var newValue = value;
+
-      if (index != lastIndex) {
+    if (key === '__proto__' || key === 'constructor' || key === 'prototype') {
-        var objValue = nested[key];
+      return object;
-        newValue = customizer ? customizer(objValue, key, nested) : undefined;
-        if (newValue === undefined) {
-          newValue = objValue == null
-            ? (isIndex(path[index + 1]) ? [] : {})
-            : objValue;
-        }
-      }
-      assignValue(nested, key, newValue);
     }
+
+    if (index != lastIndex) {
+      var objValue = nested[key];
+      newValue = customizer ? customizer(objValue, key, nested) : undefined;
+      if (newValue === undefined) {
+        newValue = isObject(objValue)
+          ? objValue
+          : (isIndex(path[index + 1]) ? [] : {});
+      }
+    }
+    assignValue(nested, key, newValue);
     nested = nested[key];
   }
   return object;

_baseSetData.js

@@ -2,7 +2,7 @@ var identity = require('./identity'),
     metaMap = require('./_metaMap');
 
 /**
- * The base implementation of `setData` without support for hot loop detection.
+ * The base implementation of `setData` without support for hot loop shorting.
  *
  * @private
  * @param {Function} func The function to associate metadata with.