Bump to v3.10.0.

README.md

@@ -1,4 +1,4 @@
-# lodash-es v3.6.0
+# lodash-es v3.10.0
 
 The [modern build](https://github.com/lodash/lodash/wiki/Build-Differences) of [lodash](https://lodash.com/) exported as [ES](https://people.mozilla.org/~jorendorff/es6-draft.html) modules.
 
@@ -7,4 +7,4 @@ Generated using [lodash-cli](https://www.npmjs.com/package/lodash-cli):
 $ lodash modularize modern exports=es -o ./
 ```
 
-See the [package source](https://github.com/lodash/lodash/tree/3.6.0-es) for more details.
+See the [package source](https://github.com/lodash/lodash/tree/3.10.0-es) for more details.

array.js

@@ -34,10 +34,12 @@ import union from './array/union';
 import uniq from './array/uniq';
 import unique from './array/unique';
 import unzip from './array/unzip';
+import unzipWith from './array/unzipWith';
 import without from './array/without';
 import xor from './array/xor';
 import zip from './array/zip';
 import zipObject from './array/zipObject';
+import zipWith from './array/zipWith';
 
 export default {
   'chunk': chunk,
@@ -76,8 +78,10 @@ export default {
   'uniq': uniq,
   'unique': unique,
   'unzip': unzip,
+  'unzipWith': unzipWith,
   'without': without,
   'xor': xor,
   'zip': zip,
-  'zipObject': zipObject
+  'zipObject': zipObject,
+  'zipWith': zipWith
 };

array/chunk.js

@@ -1,11 +1,10 @@
 import baseSlice from '../internal/baseSlice';
 import isIterateeCall from '../internal/isIterateeCall';
 
-/** Native method references. */
-var ceil = Math.ceil;
-
 /* Native method references for those with the same name as other `lodash` methods. */
-var nativeMax = Math.max;
+var nativeCeil = Math.ceil,
+    nativeFloor = Math.floor,
+    nativeMax = Math.max;
 
 /**
  * Creates an array of elements split into groups the length of `size`.
@@ -31,12 +30,12 @@ function chunk(array, size, guard) {
   if (guard ? isIterateeCall(array, size, guard) : size == null) {
     size = 1;
   } else {
-    size = nativeMax(+size || 1, 1);
+    size = nativeMax(nativeFloor(size) || 1, 1);
   }
   var index = 0,
       length = array ? array.length : 0,
       resIndex = -1,
-      result = Array(ceil(length / size));
+      result = Array(nativeCeil(length / size));
 
   while (index < length) {
     result[++resIndex] = baseSlice(array, index, (index += size));

array/difference.js

@@ -1,16 +1,13 @@
 import baseDifference from '../internal/baseDifference';
 import baseFlatten from '../internal/baseFlatten';
-import isArguments from '../lang/isArguments';
-import isArray from '../lang/isArray';
+import isArrayLike from '../internal/isArrayLike';
+import isObjectLike from '../internal/isObjectLike';
 import restParam from '../function/restParam';
 
 /**
- * Creates an array excluding all values of the provided arrays using
- * `SameValueZero` for equality comparisons.
- *
- * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
- * comparisons are like strict equality comparisons, e.g. `===`, except that
- * `NaN` matches `NaN`.
+ * Creates an array of unique `array` values not included in the other
+ * provided arrays using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+ * for equality comparisons.
  *
  * @static
  * @memberOf _
@@ -24,7 +21,7 @@ import restParam from '../function/restParam';
  * // => [1, 3]
  */
 var difference = restParam(function(array, values) {
-  return (isArray(array) || isArguments(array))
+  return (isObjectLike(array) && isArrayLike(array))
     ? baseDifference(array, baseFlatten(values, false, true))
     : [];
 });

array/indexOf.js

@@ -6,13 +6,10 @@ var nativeMax = Math.max;
 
 /**
  * Gets the index at which the first occurrence of `value` is found in `array`
- * using `SameValueZero` for equality comparisons. If `fromIndex` is negative,
- * it is used as the offset from the end of `array`. If `array` is sorted
- * providing `true` for `fromIndex` performs a faster binary search.
- *
- * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
- * comparisons are like strict equality comparisons, e.g. `===`, except that
- * `NaN` matches `NaN`.
+ * using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+ * for equality comparisons. If `fromIndex` is negative, it is used as the offset
+ * from the end of `array`. If `array` is sorted providing `true` for `fromIndex`
+ * performs a faster binary search.
  *
  * @static
  * @memberOf _
@@ -43,10 +40,9 @@ function indexOf(array, value, fromIndex) {
   if (typeof fromIndex == 'number') {
     fromIndex = fromIndex < 0 ? nativeMax(length + fromIndex, 0) : fromIndex;
   } else if (fromIndex) {
-    var index = binaryIndex(array, value),
-        other = array[index];
-
-    if (value === value ? (value === other) : (other !== other)) {
+    var index = binaryIndex(array, value);
+    if (index < length &&
+        (value === value ? (value === array[index]) : (array[index] !== array[index]))) {
       return index;
     }
     return -1;

array/intersection.js

@@ -1,17 +1,14 @@
 import baseIndexOf from '../internal/baseIndexOf';
 import cacheIndexOf from '../internal/cacheIndexOf';
 import createCache from '../internal/createCache';
-import isArguments from '../lang/isArguments';
-import isArray from '../lang/isArray';
+import isArrayLike from '../internal/isArrayLike';
+import restParam from '../function/restParam';
 
 /**
- * Creates an array of unique values in all provided arrays using `SameValueZero`
+ * Creates an array of unique values that are included in all of the provided
+ * arrays using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
  * for equality comparisons.
  *
- * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
- * comparisons are like strict equality comparisons, e.g. `===`, except that
- * `NaN` matches `NaN`.
- *
  * @static
  * @memberOf _
  * @category Array
@@ -21,36 +18,31 @@ import isArray from '../lang/isArray';
  * _.intersection([1, 2], [4, 2], [2, 1]);
  * // => [2]
  */
-function intersection() {
-  var args = [],
-      argsIndex = -1,
-      argsLength = arguments.length,
-      caches = [],
+var intersection = restParam(function(arrays) {
+  var othLength = arrays.length,
+      othIndex = othLength,
+      caches = Array(length),
       indexOf = baseIndexOf,
-      isCommon = true;
+      isCommon = true,
+      result = [];
 
-  while (++argsIndex < argsLength) {
-    var value = arguments[argsIndex];
-    if (isArray(value) || isArguments(value)) {
-      args.push(value);
-      caches.push((isCommon && value.length >= 120) ? createCache(argsIndex && value) : null);
-    }
+  while (othIndex--) {
+    var value = arrays[othIndex] = isArrayLike(value = arrays[othIndex]) ? value : [];
+    caches[othIndex] = (isCommon && value.length >= 120) ? createCache(othIndex && value) : null;
   }
-  argsLength = args.length;
-  var array = args[0],
+  var array = arrays[0],
       index = -1,
       length = array ? array.length : 0,
-      result = [],
       seen = caches[0];
 
   outer:
   while (++index < length) {
     value = array[index];
     if ((seen ? cacheIndexOf(seen, value) : indexOf(result, value, 0)) < 0) {
-      argsIndex = argsLength;
-      while (--argsIndex) {
-        var cache = caches[argsIndex];
-        if ((cache ? cacheIndexOf(cache, value) : indexOf(args[argsIndex], value, 0)) < 0) {
+      var othIndex = othLength;
+      while (--othIndex) {
+        var cache = caches[othIndex];
+        if ((cache ? cacheIndexOf(cache, value) : indexOf(arrays[othIndex], value, 0)) < 0) {
           continue outer;
         }
       }
@@ -61,6 +53,6 @@ function intersection() {
     }
   }
   return result;
-}
+});
 
 export default intersection;

array/pull.js

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

array/pullAt.js

@@ -1,15 +1,9 @@
 import baseAt from '../internal/baseAt';
 import baseCompareAscending from '../internal/baseCompareAscending';
 import baseFlatten from '../internal/baseFlatten';
-import isIndex from '../internal/isIndex';
+import basePullAt from '../internal/basePullAt';
 import restParam from '../function/restParam';
 
-/** Used for native method references. */
-var arrayProto = Array.prototype;
-
-/** Native method references. */
-var splice = arrayProto.splice;
-
 /**
  * Removes elements from `array` corresponding to the given indexes and returns
  * an array of the removed elements. Indexes may be specified as an array of
@@ -36,20 +30,10 @@ var splice = arrayProto.splice;
  * // => [10, 20]
  */
 var pullAt = restParam(function(array, indexes) {
-  array || (array = []);
   indexes = baseFlatten(indexes);
 
-  var length = indexes.length,
-      result = baseAt(array, indexes);
-
-  indexes.sort(baseCompareAscending);
-  while (length--) {
-    var index = parseFloat(indexes[length]);
-    if (index != previous && isIndex(index)) {
-      var previous = index;
-      splice.call(array, index, 1);
-    }
-  }
+  var result = baseAt(array, indexes);
+  basePullAt(array, indexes.sort(baseCompareAscending));
   return result;
 });
 

array/remove.js

@@ -1,10 +1,5 @@
 import baseCallback from '../internal/baseCallback';
-
-/** Used for native method references. */
-var arrayProto = Array.prototype;
-
-/** Native method references. */
-var splice = arrayProto.splice;
+import basePullAt from '../internal/basePullAt';
 
 /**
  * Removes all elements from `array` that `predicate` returns truthy for
@@ -46,19 +41,23 @@ var splice = arrayProto.splice;
  * // => [2, 4]
  */
 function remove(array, predicate, thisArg) {
+  var result = [];
+  if (!(array && array.length)) {
+    return result;
+  }
   var index = -1,
-      length = array ? array.length : 0,
-      result = [];
+      indexes = [],
+      length = array.length;
 
   predicate = baseCallback(predicate, thisArg, 3);
   while (++index < length) {
     var value = array[index];
     if (predicate(value, index, array)) {
       result.push(value);
-      splice.call(array, index--, 1);
-      length--;
+      indexes.push(index);
     }
   }
+  basePullAt(array, indexes);
   return result;
 }
 

array/slice.js

@@ -4,7 +4,7 @@ import isIterateeCall from '../internal/isIterateeCall';
 /**
  * Creates a slice of `array` from `start` up to, but not including, `end`.
  *
- * **Note:** This function is used instead of `Array#slice` to support node
+ * **Note:** This method is used instead of `Array#slice` to support node
  * lists in IE < 9 and to ensure dense arrays are returned.
  *
  * @static

array/union.js

@@ -3,12 +3,9 @@ import baseUniq from '../internal/baseUniq';
 import restParam from '../function/restParam';
 
 /**
- * Creates an array of unique values, in order, of the provided arrays using
- * `SameValueZero` for equality comparisons.
- *
- * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
- * comparisons are like strict equality comparisons, e.g. `===`, except that
- * `NaN` matches `NaN`.
+ * Creates an array of unique values, in order, from all of the provided arrays
+ * using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+ * for equality comparisons.
  *
  * @static
  * @memberOf _

array/uniq.js

@@ -4,12 +4,14 @@ import isIterateeCall from '../internal/isIterateeCall';
 import sortedUniq from '../internal/sortedUniq';
 
 /**
- * Creates a duplicate-value-free version of an array using `SameValueZero`
- * for equality comparisons. Providing `true` for `isSorted` performs a faster
- * search algorithm for sorted arrays. If an iteratee function is provided it
- * is invoked for each value in the array to generate the criterion by which
- * uniqueness is computed. The `iteratee` is bound to `thisArg` and invoked
- * with three arguments: (value, index, array).
+ * Creates a duplicate-free version of an array, using
+ * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+ * for equality comparisons, in which only the first occurence of each element
+ * is kept. Providing `true` for `isSorted` performs a faster search algorithm
+ * for sorted arrays. If an iteratee function is provided it is invoked for
+ * each element in the array to generate the criterion by which uniqueness
+ * is computed. The `iteratee` is bound to `thisArg` and invoked with three
+ * arguments: (value, index, array).
  *
  * If a property name is provided for `iteratee` the created `_.property`
  * style callback returns the property value of the given element.
@@ -22,10 +24,6 @@ import sortedUniq from '../internal/sortedUniq';
  * callback returns `true` for elements that have the properties of the given
  * object, else `false`.
  *
- * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
- * comparisons are like strict equality comparisons, e.g. `===`, except that
- * `NaN` matches `NaN`.
- *
  * @static
  * @memberOf _
  * @alias unique
@@ -37,8 +35,8 @@ import sortedUniq from '../internal/sortedUniq';
  * @returns {Array} Returns the new duplicate-value-free array.
  * @example
  *
- * _.uniq([1, 2, 1]);
- * // => [1, 2]
+ * _.uniq([2, 1, 2]);
+ * // => [2, 1]
  *
  * // using `isSorted`
  * _.uniq([1, 1, 2], true);
@@ -61,7 +59,7 @@ function uniq(array, isSorted, iteratee, thisArg) {
   }
   if (isSorted != null && typeof isSorted != 'boolean') {
     thisArg = iteratee;
-    iteratee = isIterateeCall(array, isSorted, thisArg) ? null : isSorted;
+    iteratee = isIterateeCall(array, isSorted, thisArg) ? undefined : isSorted;
     isSorted = false;
   }
   iteratee = iteratee == null ? iteratee : baseCallback(iteratee, thisArg, 3);

array/unzip.js

@@ -1,13 +1,14 @@
+import arrayFilter from '../internal/arrayFilter';
 import arrayMap from '../internal/arrayMap';
-import arrayMax from '../internal/arrayMax';
 import baseProperty from '../internal/baseProperty';
+import isArrayLike from '../internal/isArrayLike';
 
-/** Used to the length of n-tuples for `_.unzip`. */
-var getLength = baseProperty('length');
+/* Native method references for those with the same name as other `lodash` methods. */
+var nativeMax = Math.max;
 
 /**
  * This method is like `_.zip` except that it accepts an array of grouped
- * elements and creates an array regrouping the elements to their pre-`_.zip`
+ * elements and creates an array regrouping the elements to their pre-zip
  * configuration.
  *
  * @static
@@ -24,10 +25,19 @@ var getLength = baseProperty('length');
  * // => [['fred', 'barney'], [30, 40], [true, false]]
  */
 function unzip(array) {
+  if (!(array && array.length)) {
+    return [];
+  }
   var index = -1,
-      length = (array && array.length && arrayMax(arrayMap(array, getLength))) >>> 0,
-      result = Array(length);
+      length = 0;
 
+  array = arrayFilter(array, function(group) {
+    if (isArrayLike(group)) {
+      length = nativeMax(group.length, length);
+      return true;
+    }
+  });
+  var result = Array(length);
   while (++index < length) {
     result[index] = arrayMap(array, baseProperty(index));
   }

array/unzipWith.js

@@ -0,0 +1,41 @@
+import arrayMap from '../internal/arrayMap';
+import arrayReduce from '../internal/arrayReduce';
+import bindCallback from '../internal/bindCallback';
+import unzip from './unzip';
+
+/**
+ * This method is like `_.unzip` except that it accepts an iteratee to specify
+ * how regrouped values should be combined. The `iteratee` is bound to `thisArg`
+ * and invoked with four arguments: (accumulator, value, index, group).
+ *
+ * @static
+ * @memberOf _
+ * @category Array
+ * @param {Array} array The array of grouped elements to process.
+ * @param {Function} [iteratee] The function to combine regrouped values.
+ * @param {*} [thisArg] The `this` binding of `iteratee`.
+ * @returns {Array} Returns the new array of regrouped elements.
+ * @example
+ *
+ * var zipped = _.zip([1, 2], [10, 20], [100, 200]);
+ * // => [[1, 10, 100], [2, 20, 200]]
+ *
+ * _.unzipWith(zipped, _.add);
+ * // => [3, 30, 300]
+ */
+function unzipWith(array, iteratee, thisArg) {
+  var length = array ? array.length : 0;
+  if (!length) {
+    return [];
+  }
+  var result = unzip(array);
+  if (iteratee == null) {
+    return result;
+  }
+  iteratee = bindCallback(iteratee, thisArg, 4);
+  return arrayMap(result, function(group) {
+    return arrayReduce(group, iteratee, undefined, true);
+  });
+}
+
+export default unzipWith;

array/without.js

@@ -1,15 +1,11 @@
 import baseDifference from '../internal/baseDifference';
-import isArguments from '../lang/isArguments';
-import isArray from '../lang/isArray';
+import isArrayLike from '../internal/isArrayLike';
 import restParam from '../function/restParam';
 
 /**
- * Creates an array excluding all provided values using `SameValueZero` for
- * equality comparisons.
- *
- * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
- * comparisons are like strict equality comparisons, e.g. `===`, except that
- * `NaN` matches `NaN`.
+ * Creates an array excluding all provided values using
+ * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+ * for equality comparisons.
  *
  * @static
  * @memberOf _
@@ -23,7 +19,7 @@ import restParam from '../function/restParam';
  * // => [3]
  */
 var without = restParam(function(array, values) {
-  return (isArray(array) || isArguments(array))
+  return isArrayLike(array)
     ? baseDifference(array, values)
     : [];
 });

array/xor.js

@@ -1,10 +1,10 @@
+import arrayPush from '../internal/arrayPush';
 import baseDifference from '../internal/baseDifference';
 import baseUniq from '../internal/baseUniq';
-import isArguments from '../lang/isArguments';
-import isArray from '../lang/isArray';
+import isArrayLike from '../internal/isArrayLike';
 
 /**
- * Creates an array that is the [symmetric difference](https://en.wikipedia.org/wiki/Symmetric_difference)
+ * Creates an array of unique values that is the [symmetric difference](https://en.wikipedia.org/wiki/Symmetric_difference)
  * of the provided arrays.
  *
  * @static
@@ -23,9 +23,9 @@ function xor() {
 
   while (++index < length) {
     var array = arguments[index];
-    if (isArray(array) || isArguments(array)) {
+    if (isArrayLike(array)) {
       var result = result
-        ? baseDifference(result, array).concat(baseDifference(array, result))
+        ? arrayPush(baseDifference(result, array), baseDifference(array, result))
         : array;
     }
   }

array/zipWith.js

@@ -0,0 +1,36 @@
+import restParam from '../function/restParam';
+import unzipWith from './unzipWith';
+
+/**
+ * This method is like `_.zip` except that it accepts an iteratee to specify
+ * how grouped values should be combined. The `iteratee` is bound to `thisArg`
+ * and invoked with four arguments: (accumulator, value, index, group).
+ *
+ * @static
+ * @memberOf _
+ * @category Array
+ * @param {...Array} [arrays] The arrays to process.
+ * @param {Function} [iteratee] The function to combine grouped values.
+ * @param {*} [thisArg] The `this` binding of `iteratee`.
+ * @returns {Array} Returns the new array of grouped elements.
+ * @example
+ *
+ * _.zipWith([1, 2], [10, 20], [100, 200], _.add);
+ * // => [111, 222]
+ */
+var zipWith = restParam(function(arrays) {
+  var length = arrays.length,
+      iteratee = length > 2 ? arrays[length - 2] : undefined,
+      thisArg = length > 1 ? arrays[length - 1] : undefined;
+
+  if (length > 2 && typeof iteratee == 'function') {
+    length -= 2;
+  } else {
+    iteratee = (length > 1 && typeof thisArg == 'function') ? (--length, thisArg) : undefined;
+    thisArg = undefined;
+  }
+  arrays.length = length;
+  return unzipWith(arrays, iteratee, thisArg);
+});
+
+export default zipWith;

chain.js

@@ -1,5 +1,6 @@
 import chain from './chain/chain';
 import commit from './chain/commit';
+import concat from './chain/concat';
 import lodash from './chain/lodash';
 import plant from './chain/plant';
 import reverse from './chain/reverse';
@@ -15,6 +16,7 @@ import wrapperChain from './chain/wrapperChain';
 export default {
   'chain': chain,
   'commit': commit,
+  'concat': concat,
   'lodash': lodash,
   'plant': plant,
   'reverse': reverse,

chain/concat.js

@@ -0,0 +1,2 @@
+import wrapperConcat from './wrapperConcat'
+export default wrapperConcat;

chain/lodash.js

@@ -14,15 +14,16 @@ var hasOwnProperty = objectProto.hasOwnProperty;
 /**
  * Creates a `lodash` object which wraps `value` to enable implicit chaining.
  * Methods that operate on and return arrays, collections, and functions can
- * be chained together. Methods that return a boolean or single value will
- * automatically end the chain returning the unwrapped value. Explicit chaining
- * may be enabled using `_.chain`. The execution of chained methods is lazy,
- * that is, execution is deferred until `_#value` is implicitly or explicitly
- * called.
+ * be chained together. Methods that retrieve a single value or may return a
+ * primitive value will automatically end the chain returning the unwrapped
+ * value. Explicit chaining may be enabled using `_.chain`. The execution of
+ * chained methods is lazy, that is, execution is deferred until `_#value`
+ * is implicitly or explicitly called.
  *
  * Lazy evaluation allows several methods to support shortcut fusion. Shortcut
- * fusion is an optimization that merges iteratees to avoid creating intermediate
- * arrays and reduce the number of iteratee executions.
+ * fusion is an optimization strategy which merge iteratee calls; this can help
+ * to avoid the creation of intermediate data structures and greatly reduce the
+ * number of iteratee executions.
  *
  * Chaining is supported in custom builds as long as the `_#value` method is
  * directly or indirectly included in the build.
@@ -45,35 +46,37 @@ var hasOwnProperty = objectProto.hasOwnProperty;
  * The chainable wrapper methods are:
  * `after`, `ary`, `assign`, `at`, `before`, `bind`, `bindAll`, `bindKey`,
  * `callback`, `chain`, `chunk`, `commit`, `compact`, `concat`, `constant`,
- * `countBy`, `create`, `curry`, `debounce`, `defaults`, `defer`, `delay`,
- * `difference`, `drop`, `dropRight`, `dropRightWhile`, `dropWhile`, `fill`,
- * `filter`, `flatten`, `flattenDeep`, `flow`, `flowRight`, `forEach`,
- * `forEachRight`, `forIn`, `forInRight`, `forOwn`, `forOwnRight`, `functions`,
- * `groupBy`, `indexBy`, `initial`, `intersection`, `invert`, `invoke`, `keys`,
- * `keysIn`, `map`, `mapValues`, `matches`, `matchesProperty`, `memoize`, `merge`,
- * `mixin`, `negate`, `noop`, `omit`, `once`, `pairs`, `partial`, `partialRight`,
+ * `countBy`, `create`, `curry`, `debounce`, `defaults`, `defaultsDeep`,
+ * `defer`, `delay`, `difference`, `drop`, `dropRight`, `dropRightWhile`,
+ * `dropWhile`, `fill`, `filter`, `flatten`, `flattenDeep`, `flow`, `flowRight`,
+ * `forEach`, `forEachRight`, `forIn`, `forInRight`, `forOwn`, `forOwnRight`,
+ * `functions`, `groupBy`, `indexBy`, `initial`, `intersection`, `invert`,
+ * `invoke`, `keys`, `keysIn`, `map`, `mapKeys`, `mapValues`, `matches`,
+ * `matchesProperty`, `memoize`, `merge`, `method`, `methodOf`, `mixin`,
+ * `modArgs`, `negate`, `omit`, `once`, `pairs`, `partial`, `partialRight`,
  * `partition`, `pick`, `plant`, `pluck`, `property`, `propertyOf`, `pull`,
- * `pullAt`, `push`, `range`, `rearg`, `reject`, `remove`, `rest`, `reverse`,
- * `shuffle`, `slice`, `sort`, `sortBy`, `sortByAll`, `sortByOrder`, `splice`,
- * `spread`, `take`, `takeRight`, `takeRightWhile`, `takeWhile`, `tap`,
- * `throttle`, `thru`, `times`, `toArray`, `toPlainObject`, `transform`,
- * `union`, `uniq`, `unshift`, `unzip`, `values`, `valuesIn`, `where`,
- * `without`, `wrap`, `xor`, `zip`, and `zipObject`
+ * `pullAt`, `push`, `range`, `rearg`, `reject`, `remove`, `rest`, `restParam`,
+ * `reverse`, `set`, `shuffle`, `slice`, `sort`, `sortBy`, `sortByAll`,
+ * `sortByOrder`, `splice`, `spread`, `take`, `takeRight`, `takeRightWhile`,
+ * `takeWhile`, `tap`, `throttle`, `thru`, `times`, `toArray`, `toPlainObject`,
+ * `transform`, `union`, `uniq`, `unshift`, `unzip`, `unzipWith`, `values`,
+ * `valuesIn`, `where`, `without`, `wrap`, `xor`, `zip`, `zipObject`, `zipWith`
  *
  * The wrapper methods that are **not** chainable by default are:
- * `add`, `attempt`, `camelCase`, `capitalize`, `clone`, `cloneDeep`, `deburr`,
- * `endsWith`, `escape`, `escapeRegExp`, `every`, `find`, `findIndex`, `findKey`,
- * `findLast`, `findLastIndex`, `findLastKey`, `findWhere`, `first`, `has`,
- * `identity`, `includes`, `indexOf`, `inRange`, `isArguments`, `isArray`,
- * `isBoolean`, `isDate`, `isElement`, `isEmpty`, `isEqual`, `isError`,
- * `isFinite`,`isFunction`, `isMatch`, `isNative`, `isNaN`, `isNull`, `isNumber`,
- * `isObject`, `isPlainObject`, `isRegExp`, `isString`, `isUndefined`,
- * `isTypedArray`, `join`, `kebabCase`, `last`, `lastIndexOf`, `max`, `min`,
- * `noConflict`, `now`, `pad`, `padLeft`, `padRight`, `parseInt`, `pop`,
- * `random`, `reduce`, `reduceRight`, `repeat`, `result`, `runInContext`,
- * `shift`, `size`, `snakeCase`, `some`, `sortedIndex`, `sortedLastIndex`,
- * `startCase`, `startsWith`, `sum`, `template`, `trim`, `trimLeft`,
- * `trimRight`, `trunc`, `unescape`, `uniqueId`, `value`, and `words`
+ * `add`, `attempt`, `camelCase`, `capitalize`, `ceil`, `clone`, `cloneDeep`,
+ * `deburr`, `endsWith`, `escape`, `escapeRegExp`, `every`, `find`, `findIndex`,
+ * `findKey`, `findLast`, `findLastIndex`, `findLastKey`, `findWhere`, `first`,
+ * `floor`, `get`, `gt`, `gte`, `has`, `identity`, `includes`, `indexOf`,
+ * `inRange`, `isArguments`, `isArray`, `isBoolean`, `isDate`, `isElement`,
+ * `isEmpty`, `isEqual`, `isError`, `isFinite` `isFunction`, `isMatch`,
+ * `isNative`, `isNaN`, `isNull`, `isNumber`, `isObject`, `isPlainObject`,
+ * `isRegExp`, `isString`, `isUndefined`, `isTypedArray`, `join`, `kebabCase`,
+ * `last`, `lastIndexOf`, `lt`, `lte`, `max`, `min`, `noConflict`, `noop`,
+ * `now`, `pad`, `padLeft`, `padRight`, `parseInt`, `pop`, `random`, `reduce`,
+ * `reduceRight`, `repeat`, `result`, `round`, `runInContext`, `shift`, `size`,
+ * `snakeCase`, `some`, `sortedIndex`, `sortedLastIndex`, `startCase`,
+ * `startsWith`, `sum`, `template`, `trim`, `trimLeft`, `trimRight`, `trunc`,
+ * `unescape`, `uniqueId`, `value`, and `words`
  *
  * The wrapper method `sample` will return a wrapped value when `n` is provided,
  * otherwise an unwrapped value is returned.
@@ -88,8 +91,8 @@ var hasOwnProperty = objectProto.hasOwnProperty;
  * var wrapped = _([1, 2, 3]);
  *
  * // returns an unwrapped value
- * wrapped.reduce(function(sum, n) {
- *   return sum + n;
+ * wrapped.reduce(function(total, n) {
+ *   return total + n;
  * });
  * // => 6
  *

chain/wrapperCommit.js

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

chain/wrapperConcat.js

@@ -0,0 +1,34 @@
+import arrayConcat from '../internal/arrayConcat';
+import baseFlatten from '../internal/baseFlatten';
+import isArray from '../lang/isArray';
+import restParam from '../function/restParam';
+import toObject from '../internal/toObject';
+
+/**
+ * Creates a new array joining a wrapped array with any additional arrays
+ * and/or values.
+ *
+ * @name concat
+ * @memberOf _
+ * @category Chain
+ * @param {...*} [values] The values to concatenate.
+ * @returns {Array} Returns the new concatenated array.
+ * @example
+ *
+ * var array = [1];
+ * var wrapped = _(array).concat(2, [3], [[4]]);
+ *
+ * console.log(wrapped.value());
+ * // => [1, 2, 3, [4]]
+ *
+ * console.log(array);
+ * // => [1]
+ */
+var wrapperConcat = restParam(function(values) {
+  values = baseFlatten(values);
+  return this.thru(function(array) {
+    return arrayConcat(isArray(array) ? array : [toObject(array)], values);
+  });
+});
+
+export default wrapperConcat;

chain/wrapperPlant.js

@@ -11,17 +11,17 @@ import wrapperClone from '../internal/wrapperClone';
  * @example
  *
  * var array = [1, 2];
- * var wrapper = _(array).map(function(value) {
+ * var wrapped = _(array).map(function(value) {
  *   return Math.pow(value, 2);
  * });
  *
  * var other = [3, 4];
- * var otherWrapper = wrapper.plant(other);
+ * var otherWrapped = wrapped.plant(other);
  *
- * otherWrapper.value();
+ * otherWrapped.value();
  * // => [9, 16]
  *
- * wrapper.value();
+ * wrapped.value();
  * // => [1, 4]
  */
 function wrapperPlant(value) {

chain/wrapperReverse.js

@@ -24,15 +24,20 @@ import thru from './thru';
  */
 function wrapperReverse() {
   var value = this.__wrapped__;
+
+  var interceptor = function(value) {
+    return (wrapped && wrapped.__dir__ < 0) ? value : value.reverse();
+  };
   if (value instanceof LazyWrapper) {
+    var wrapped = value;
     if (this.__actions__.length) {
-      value = new LazyWrapper(this);
+      wrapped = new LazyWrapper(this);
     }
-    return new LodashWrapper(value.reverse(), this.__chain__);
+    wrapped = wrapped.reverse();
+    wrapped.__actions__.push({ 'func': thru, 'args': [interceptor], 'thisArg': undefined });
+    return new LodashWrapper(wrapped, this.__chain__);
   }
-  return this.thru(function(value) {
-    return value.reverse();
-  });
+  return this.thru(interceptor);
 }
 
 export default wrapperReverse;

collection/at.js

@@ -1,8 +1,6 @@
 import baseAt from '../internal/baseAt';
 import baseFlatten from '../internal/baseFlatten';
-import isLength from '../internal/isLength';
 import restParam from '../function/restParam';
-import toIterable from '../internal/toIterable';
 
 /**
  * Creates an array of elements corresponding to the given keys, or indexes,
@@ -25,10 +23,6 @@ import toIterable from '../internal/toIterable';
  * // => ['barney', 'pebbles']
  */
 var at = restParam(function(collection, props) {
-  var length = collection ? collection.length : 0;
-  if (isLength(length)) {
-    collection = toIterable(collection);
-  }
   return baseAt(collection, baseFlatten(props));
 });
 

collection/every.js

@@ -55,9 +55,9 @@ import isIterateeCall from '../internal/isIterateeCall';
 function every(collection, predicate, thisArg) {
   var func = isArray(collection) ? arrayEvery : baseEvery;
   if (thisArg && isIterateeCall(collection, predicate, thisArg)) {
-    predicate = null;
+    predicate = undefined;
   }
-  if (typeof predicate != 'function' || typeof thisArg != 'undefined') {
+  if (typeof predicate != 'function' || thisArg !== undefined) {
     predicate = baseCallback(predicate, thisArg, 3);
   }
   return func(collection, predicate);

collection/forEach.js

@@ -5,10 +5,10 @@ import createForEach from '../internal/createForEach';
 /**
  * Iterates over elements of `collection` invoking `iteratee` for each element.
  * The `iteratee` is bound to `thisArg` and invoked with three arguments:
- * (value, index|key, collection). Iterator functions may exit iteration early
+ * (value, index|key, collection). Iteratee functions may exit iteration early
  * by explicitly returning `false`.
  *
- * **Note:** As with other "Collections" methods, objects with a `length` property
+ * **Note:** As with other "Collections" methods, objects with a "length" property
  * are iterated like arrays. To avoid this behavior `_.forIn` or `_.forOwn`
  * may be used for object iteration.
  *

collection/includes.js

@@ -1,4 +1,5 @@
 import baseIndexOf from '../internal/baseIndexOf';
+import getLength from '../internal/getLength';
 import isArray from '../lang/isArray';
 import isIterateeCall from '../internal/isIterateeCall';
 import isLength from '../internal/isLength';
@@ -9,13 +10,10 @@ import values from '../object/values';
 var nativeMax = Math.max;
 
 /**
- * Checks if `value` is in `collection` using `SameValueZero` for equality
- * comparisons. If `fromIndex` is negative, it is used as the offset from
- * the end of `collection`.
- *
- * **Note:** [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
- * comparisons are like strict equality comparisons, e.g. `===`, except that
- * `NaN` matches `NaN`.
+ * Checks if `value` is in `collection` using
+ * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
+ * for equality comparisons. If `fromIndex` is negative, it is used as the offset
+ * from the end of `collection`.
  *
  * @static
  * @memberOf _
@@ -41,22 +39,19 @@ var nativeMax = Math.max;
  * // => true
  */
 function includes(collection, target, fromIndex, guard) {
-  var length = collection ? collection.length : 0;
+  var length = collection ? getLength(collection) : 0;
   if (!isLength(length)) {
     collection = values(collection);
     length = collection.length;
   }
-  if (!length) {
-    return false;
-  }
   if (typeof fromIndex != 'number' || (guard && isIterateeCall(target, fromIndex, guard))) {
     fromIndex = 0;
   } else {
     fromIndex = fromIndex < 0 ? nativeMax(length + fromIndex, 0) : (fromIndex || 0);
   }
   return (typeof collection == 'string' || !isArray(collection) && isString(collection))
-    ? (fromIndex < length && collection.indexOf(target, fromIndex) > -1)
-    : (baseIndexOf(collection, target, fromIndex) > -1);
+    ? (fromIndex <= length && collection.indexOf(target, fromIndex) > -1)
+    : (!!length && baseIndexOf(collection, target, fromIndex) > -1);
 }
 
 export default includes;

collection/invoke.js

@@ -1,18 +1,20 @@
 import baseEach from '../internal/baseEach';
-import isLength from '../internal/isLength';
+import invokePath from '../internal/invokePath';
+import isArrayLike from '../internal/isArrayLike';
+import isKey from '../internal/isKey';
 import restParam from '../function/restParam';
 
 /**
- * Invokes the method named by `methodName` on each element in `collection`,
- * returning an array of the results of each invoked method. Any additional
- * arguments are provided to each invoked method. If `methodName` is a function
- * it is invoked for, and `this` bound to, each element in `collection`.
+ * Invokes the method at `path` of each element in `collection`, returning
+ * an array of the results of each invoked method. Any additional arguments
+ * are provided to each invoked method. If `methodName` is a function it is
+ * invoked for, and `this` bound to, each element in `collection`.
  *
  * @static
  * @memberOf _
  * @category Collection
  * @param {Array|Object|string} collection The collection to iterate over.
- * @param {Function|string} methodName The name of the method to invoke or
+ * @param {Array|Function|string} path The path of the method to invoke or
  *  the function invoked per iteration.
  * @param {...*} [args] The arguments to invoke the method with.
  * @returns {Array} Returns the array of results.
@@ -24,15 +26,15 @@ import restParam from '../function/restParam';
  * _.invoke([123, 456], String.prototype.split, '');
  * // => [['1', '2', '3'], ['4', '5', '6']]
  */
-var invoke = restParam(function(collection, methodName, args) {
+var invoke = restParam(function(collection, path, args) {
   var index = -1,
-      isFunc = typeof methodName == 'function',
-      length = collection ? collection.length : 0,
-      result = isLength(length) ? Array(length) : [];
+      isFunc = typeof path == 'function',
+      isProp = isKey(path),
+      result = isArrayLike(collection) ? Array(collection.length) : [];
 
   baseEach(collection, function(value) {
-    var func = isFunc ? methodName : (value != null && value[methodName]);
-    result[++index] = func ? func.apply(value, args) : undefined;
+    var func = isFunc ? path : ((isProp && value != null) ? value[path] : undefined);
+    result[++index] = func ? func.apply(value, args) : invokePath(value, path, args);
   });
   return result;
 });

collection/map.js

@@ -19,14 +19,15 @@ import isArray from '../lang/isArray';
  * callback returns `true` for elements that have the properties of the given
  * object, else `false`.
  *
- * Many lodash methods are guarded to work as interatees for methods like
+ * Many lodash methods are guarded to work as iteratees for methods like
  * `_.every`, `_.filter`, `_.map`, `_.mapValues`, `_.reject`, and `_.some`.
  *
  * The guarded methods are:
- * `ary`, `callback`, `chunk`, `clone`, `create`, `curry`, `curryRight`, `drop`,
- * `dropRight`, `every`, `fill`, `flatten`, `invert`, `max`, `min`, `parseInt`,
- * `slice`, `sortBy`, `take`, `takeRight`, `template`, `trim`, `trimLeft`,
- * `trimRight`, `trunc`, `random`, `range`, `sample`, `some`, `uniq`, and `words`
+ * `ary`, `callback`, `chunk`, `clone`, `create`, `curry`, `curryRight`,
+ * `drop`, `dropRight`, `every`, `fill`, `flatten`, `invert`, `max`, `min`,
+ * `parseInt`, `slice`, `sortBy`, `take`, `takeRight`, `template`, `trim`,
+ * `trimLeft`, `trimRight`, `trunc`, `random`, `range`, `sample`, `some`,
+ * `sum`, `uniq`, and `words`
  *
  * @static
  * @memberOf _
@@ -35,7 +36,6 @@ import isArray from '../lang/isArray';
  * @param {Array|Object|string} collection The collection to iterate over.
  * @param {Function|Object|string} [iteratee=_.identity] The function invoked
  *  per iteration.
- *  create a `_.property` or `_.matches` style callback respectively.
  * @param {*} [thisArg] The `this` binding of `iteratee`.
  * @returns {Array} Returns the new mapped array.
  * @example

collection/pluck.js

@@ -1,14 +1,14 @@
-import baseProperty from '../internal/baseProperty';
 import map from './map';
+import property from '../utility/property';
 
 /**
- * Gets the value of `key` from all elements in `collection`.
+ * Gets the property value of `path` from all elements in `collection`.
  *
  * @static
  * @memberOf _
  * @category Collection
  * @param {Array|Object|string} collection The collection to iterate over.
- * @param {string} key The key of the property to pluck.
+ * @param {Array|string} path The path of the property to pluck.
  * @returns {Array} Returns the property values.
  * @example
  *
@@ -24,8 +24,8 @@ import map from './map';
  * _.pluck(userIndex, 'age');
  * // => [36, 40] (iteration order is not guaranteed)
  */
-function pluck(collection, key) {
-  return map(collection, baseProperty(key));
+function pluck(collection, path) {
+  return map(collection, property(path));
 }
 
 export default pluck;

collection/reduce.js

@@ -10,11 +10,12 @@ import createReduce from '../internal/createReduce';
  * value. The `iteratee` is bound to `thisArg` and invoked with four arguments:
  * (accumulator, value, index|key, collection).
  *
- * Many lodash methods are guarded to work as interatees for methods like
+ * Many lodash methods are guarded to work as iteratees for methods like
  * `_.reduce`, `_.reduceRight`, and `_.transform`.
  *
  * The guarded methods are:
- * `assign`, `defaults`, `includes`, `merge`, `sortByAll`, and `sortByOrder`
+ * `assign`, `defaults`, `defaultsDeep`, `includes`, `merge`, `sortByAll`,
+ * and `sortByOrder`
  *
  * @static
  * @memberOf _
@@ -27,8 +28,8 @@ import createReduce from '../internal/createReduce';
  * @returns {*} Returns the accumulated value.
  * @example
  *
- * _.reduce([1, 2], function(sum, n) {
- *   return sum + n;
+ * _.reduce([1, 2], function(total, n) {
+ *   return total + n;
  * });
  * // => 3
  *

collection/reduceRight.js

@@ -24,6 +24,6 @@ import createReduce from '../internal/createReduce';
  * }, []);
  * // => [4, 5, 2, 3, 0, 1]
  */
-var reduceRight =  createReduce(arrayReduceRight, baseEachRight);
+var reduceRight = createReduce(arrayReduceRight, baseEachRight);
 
 export default reduceRight;

collection/reject.js

@@ -7,17 +7,6 @@ import isArray from '../lang/isArray';
  * The opposite of `_.filter`; this method returns the elements of `collection`
  * that `predicate` does **not** return truthy for.
  *
- * If a property name is provided for `predicate` the created `_.property`
- * style callback returns the property value of the given element.
- *
- * If a value is also provided for `thisArg` the created `_.matchesProperty`
- * style callback returns `true` for elements that have a matching property
- * value, else `false`.
- *
- * If an object is provided for `predicate` the created `_.matches` style
- * callback returns `true` for elements that have the properties of the given
- * object, else `false`.
- *
  * @static
  * @memberOf _
  * @category Collection

collection/sample.js

@@ -1,6 +1,6 @@
 import baseRandom from '../internal/baseRandom';
 import isIterateeCall from '../internal/isIterateeCall';
-import shuffle from './shuffle';
+import toArray from '../lang/toArray';
 import toIterable from '../internal/toIterable';
 
 /* Native method references for those with the same name as other `lodash` methods. */
@@ -30,8 +30,20 @@ function sample(collection, n, guard) {
     var length = collection.length;
     return length > 0 ? collection[baseRandom(0, length - 1)] : undefined;
   }
-  var result = shuffle(collection);
-  result.length = nativeMin(n < 0 ? 0 : (+n || 0), result.length);
+  var index = -1,
+      result = toArray(collection),
+      length = result.length,
+      lastIndex = length - 1;
+
+  n = nativeMin(n < 0 ? 0 : (+n || 0), length);
+  while (++index < n) {
+    var rand = baseRandom(index, lastIndex),
+        value = result[rand];
+
+    result[rand] = result[index];
+    result[index] = value;
+  }
+  result.length = n;
   return result;
 }
 

collection/shuffle.js

@@ -1,5 +1,7 @@
-import baseRandom from '../internal/baseRandom';
-import toIterable from '../internal/toIterable';
+import sample from './sample';
+
+/** Used as references for `-Infinity` and `Infinity`. */
+var POSITIVE_INFINITY = Number.POSITIVE_INFINITY;
 
 /**
  * Creates an array of shuffled values, using a version of the
@@ -16,20 +18,7 @@ import toIterable from '../internal/toIterable';
  * // => [4, 1, 3, 2]
  */
 function shuffle(collection) {
-  collection = toIterable(collection);
-
-  var index = -1,
-      length = collection.length,
-      result = Array(length);
-
-  while (++index < length) {
-    var rand = baseRandom(0, index);
-    if (index != rand) {
-      result[index] = result[rand];
-    }
-    result[rand] = collection[index];
-  }
-  return result;
+  return sample(collection, POSITIVE_INFINITY);
 }
 
 export default shuffle;

collection/size.js

@@ -1,3 +1,4 @@
+import getLength from '../internal/getLength';
 import isLength from '../internal/isLength';
 import keys from '../object/keys';
 
@@ -22,7 +23,7 @@ import keys from '../object/keys';
  * // => 7
  */
 function size(collection) {
-  var length = collection ? collection.length : 0;
+  var length = collection ? getLength(collection) : 0;
   return isLength(length) ? length : keys(collection).length;
 }
 

collection/some.js

@@ -56,9 +56,9 @@ import isIterateeCall from '../internal/isIterateeCall';
 function some(collection, predicate, thisArg) {
   var func = isArray(collection) ? arraySome : baseSome;
   if (thisArg && isIterateeCall(collection, predicate, thisArg)) {
-    predicate = null;
+    predicate = undefined;
   }
-  if (typeof predicate != 'function' || typeof thisArg != 'undefined') {
+  if (typeof predicate != 'function' || thisArg !== undefined) {
     predicate = baseCallback(predicate, thisArg, 3);
   }
   return func(collection, predicate);

collection/sortBy.js

@@ -1,9 +1,8 @@
 import baseCallback from '../internal/baseCallback';
-import baseEach from '../internal/baseEach';
+import baseMap from '../internal/baseMap';
 import baseSortBy from '../internal/baseSortBy';
 import compareAscending from '../internal/compareAscending';
 import isIterateeCall from '../internal/isIterateeCall';
-import isLength from '../internal/isLength';
 
 /**
  * Creates an array of elements, sorted in ascending order by the results of
@@ -27,9 +26,8 @@ import isLength from '../internal/isLength';
  * @memberOf _
  * @category Collection
  * @param {Array|Object|string} collection The collection to iterate over.
- * @param {Array|Function|Object|string} [iteratee=_.identity] The function
- *  invoked per iteration. If a property name or an object is provided it is
- *  used to create a `_.property` or `_.matches` style callback respectively.
+ * @param {Function|Object|string} [iteratee=_.identity] The function invoked
+ *  per iteration.
  * @param {*} [thisArg] The `this` binding of `iteratee`.
  * @returns {Array} Returns the new sorted array.
  * @example
@@ -58,16 +56,14 @@ function sortBy(collection, iteratee, thisArg) {
   if (collection == null) {
     return [];
   }
-  var index = -1,
-      length = collection.length,
-      result = isLength(length) ? Array(length) : [];
-
   if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
-    iteratee = null;
+    iteratee = undefined;
   }
+  var index = -1;
   iteratee = baseCallback(iteratee, thisArg, 3);
-  baseEach(collection, function(value, key, collection) {
-    result[++index] = { 'criteria': iteratee(value, key, collection), 'index': index, 'value': value };
+
+  var result = baseMap(collection, function(value, key, collection) {
+    return { 'criteria': iteratee(value, key, collection), 'index': ++index, 'value': value };
   });
   return baseSortBy(result, compareAscending);
 }

collection/sortByAll.js

@@ -1,48 +1,52 @@
 import baseFlatten from '../internal/baseFlatten';
 import baseSortByOrder from '../internal/baseSortByOrder';
 import isIterateeCall from '../internal/isIterateeCall';
+import restParam from '../function/restParam';
 
 /**
- * This method is like `_.sortBy` except that it sorts by property names
- * instead of an iteratee function.
+ * This method is like `_.sortBy` except that it can sort by multiple iteratees
+ * or property names.
+ *
+ * If a property name is provided for an iteratee the created `_.property`
+ * style callback returns the property value of the given element.
+ *
+ * If an object is provided for an iteratee the created `_.matches` style
+ * callback returns `true` for elements that have the properties of the given
+ * object, else `false`.
  *
  * @static
  * @memberOf _
  * @category Collection
  * @param {Array|Object|string} collection The collection to iterate over.
- * @param {...(string|string[])} props The property names to sort by,
- *  specified as individual property names or arrays of property names.
+ * @param {...(Function|Function[]|Object|Object[]|string|string[])} iteratees
+ *  The iteratees to sort by, specified as individual values or arrays of values.
  * @returns {Array} Returns the new sorted array.
  * @example
  *
  * var users = [
+ *   { 'user': 'fred',   'age': 48 },
  *   { 'user': 'barney', 'age': 36 },
- *   { 'user': 'fred',   'age': 40 },
- *   { 'user': 'barney', 'age': 26 },
- *   { 'user': 'fred',   'age': 30 }
+ *   { 'user': 'fred',   'age': 42 },
+ *   { 'user': 'barney', 'age': 34 }
  * ];
  *
  * _.map(_.sortByAll(users, ['user', 'age']), _.values);
- * // => [['barney', 26], ['barney', 36], ['fred', 30], ['fred', 40]]
+ * // => [['barney', 34], ['barney', 36], ['fred', 42], ['fred', 48]]
+ *
+ * _.map(_.sortByAll(users, 'user', function(chr) {
+ *   return Math.floor(chr.age / 10);
+ * }), _.values);
+ * // => [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 42]]
  */
-function sortByAll() {
-  var args = arguments,
-      collection = args[0],
-      guard = args[3],
-      index = 0,
-      length = args.length - 1;
-
+var sortByAll = restParam(function(collection, iteratees) {
   if (collection == null) {
     return [];
   }
-  var props = Array(length);
-  while (index < length) {
-    props[index] = args[++index];
+  var guard = iteratees[2];
+  if (guard && isIterateeCall(iteratees[0], iteratees[1], guard)) {
+    iteratees.length = 1;
   }
-  if (guard && isIterateeCall(args[1], args[2], guard)) {
-    props = args[1];
-  }
-  return baseSortByOrder(collection, baseFlatten(props), []);
-}
+  return baseSortByOrder(collection, baseFlatten(iteratees), []);
+});
 
 export default sortByAll;

collection/sortByOrder.js

@@ -4,45 +4,52 @@ import isIterateeCall from '../internal/isIterateeCall';
 
 /**
  * This method is like `_.sortByAll` except that it allows specifying the
- * sort orders of the property names to sort by. A truthy value in `orders`
- * will sort the corresponding property name in ascending order while a
- * falsey value will sort it in descending order.
+ * sort orders of the iteratees to sort by. If `orders` is unspecified, all
+ * values are sorted in ascending order. Otherwise, a value is sorted in
+ * ascending order if its corresponding order is "asc", and descending if "desc".
+ *
+ * If a property name is provided for an iteratee the created `_.property`
+ * style callback returns the property value of the given element.
+ *
+ * If an object is provided for an iteratee the created `_.matches` style
+ * callback returns `true` for elements that have the properties of the given
+ * object, else `false`.
  *
  * @static
  * @memberOf _
  * @category Collection
  * @param {Array|Object|string} collection The collection to iterate over.
- * @param {string[]} props The property names to sort by.
- * @param {boolean[]} orders The sort orders of `props`.
+ * @param {Function[]|Object[]|string[]} iteratees The iteratees to sort by.
+ * @param {boolean[]} [orders] The sort orders of `iteratees`.
  * @param- {Object} [guard] Enables use as a callback for functions like `_.reduce`.
  * @returns {Array} Returns the new sorted array.
  * @example
  *
  * var users = [
- *   { 'user': 'barney', 'age': 26 },
- *   { 'user': 'fred',   'age': 40 },
- *   { 'user': 'barney', 'age': 36 },
- *   { 'user': 'fred',   'age': 30 }
+ *   { 'user': 'fred',   'age': 48 },
+ *   { 'user': 'barney', 'age': 34 },
+ *   { 'user': 'fred',   'age': 42 },
+ *   { 'user': 'barney', 'age': 36 }
  * ];
  *
  * // sort by `user` in ascending order and by `age` in descending order
- * _.map(_.sortByOrder(users, ['user', 'age'], [true, false]), _.values);
- * // => [['barney', 36], ['barney', 26], ['fred', 40], ['fred', 30]]
+ * _.map(_.sortByOrder(users, ['user', 'age'], ['asc', 'desc']), _.values);
+ * // => [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 42]]
  */
-function sortByOrder(collection, props, orders, guard) {
+function sortByOrder(collection, iteratees, orders, guard) {
   if (collection == null) {
     return [];
   }
-  if (guard && isIterateeCall(props, orders, guard)) {
-    orders = null;
+  if (guard && isIterateeCall(iteratees, orders, guard)) {
+    orders = undefined;
   }
-  if (!isArray(props)) {
-    props = props == null ? [] : [props];
+  if (!isArray(iteratees)) {
+    iteratees = iteratees == null ? [] : [iteratees];
   }
   if (!isArray(orders)) {
     orders = orders == null ? [] : [orders];
   }
-  return baseSortByOrder(collection, props, orders);
+  return baseSortByOrder(collection, iteratees, orders);
 }
 
 export default sortByOrder;

date/now.js

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

function.js

@@ -14,6 +14,7 @@ import delay from './function/delay';
 import flow from './function/flow';
 import flowRight from './function/flowRight';
 import memoize from './function/memoize';
+import modArgs from './function/modArgs';
 import negate from './function/negate';
 import once from './function/once';
 import partial from './function/partial';
@@ -41,6 +42,7 @@ export default {
   'flow': flow,
   'flowRight': flowRight,
   'memoize': memoize,
+  'modArgs': modArgs,
   'negate': negate,
   'once': once,
   'partial': partial,

function/ary.js

@@ -25,10 +25,10 @@ var nativeMax = Math.max;
  */
 function ary(func, n, guard) {
   if (guard && isIterateeCall(func, n, guard)) {
-    n = null;
+    n = undefined;
   }
   n = (func && n == null) ? func.length : nativeMax(+n || 0, 0);
-  return createWrapper(func, ARY_FLAG, null, null, null, null, n);
+  return createWrapper(func, ARY_FLAG, undefined, undefined, undefined, undefined, n);
 }
 
 export default ary;

function/before.js

@@ -31,8 +31,9 @@ function before(n, func) {
   return function() {
     if (--n > 0) {
       result = func.apply(this, arguments);
-    } else {
-      func = null;
+    }
+    if (n <= 1) {
+      func = undefined;
     }
     return result;
   };

function/bind.js

@@ -14,7 +14,7 @@ var BIND_FLAG = 1,
  * The `_.bind.placeholder` value, which defaults to `_` in monolithic builds,
  * may be used as a placeholder for partially applied arguments.
  *
- * **Note:** Unlike native `Function#bind` this method does not set the `length`
+ * **Note:** Unlike native `Function#bind` this method does not set the "length"
  * property of bound functions.
  *
  * @static

function/bindAll.js

@@ -12,7 +12,7 @@ var BIND_FLAG = 1;
  * of method names. If no method names are provided all enumerable function
  * properties, own and inherited, of `object` are bound.
  *
- * **Note:** This method does not set the `length` property of bound functions.
+ * **Note:** This method does not set the "length" property of bound functions.
  *
  * @static
  * @memberOf _

function/bindKey.js

@@ -13,7 +13,7 @@ var BIND_FLAG = 1,
  *
  * This method differs from `_.bind` by allowing bound functions to reference
  * methods that may be redefined or don't yet exist.
- * See [Peter Michaux's article](http://michaux.ca/articles/lazy-function-definition-pattern)
+ * See [Peter Michaux's article](http://peter.michaux.ca/articles/lazy-function-definition-pattern)
  * for more details.
  *
  * The `_.bindKey.placeholder` value, which defaults to `_` in monolithic

function/curry.js

@@ -13,7 +13,7 @@ var CURRY_FLAG = 8;
  * The `_.curry.placeholder` value, which defaults to `_` in monolithic builds,
  * may be used as a placeholder for provided arguments.
  *
- * **Note:** This method does not set the `length` property of curried functions.
+ * **Note:** This method does not set the "length" property of curried functions.
  *
  * @static
  * @memberOf _

function/curryRight.js

@@ -10,7 +10,7 @@ var CURRY_RIGHT_FLAG = 16;
  * The `_.curryRight.placeholder` value, which defaults to `_` in monolithic
  * builds, may be used as a placeholder for provided arguments.
  *
- * **Note:** This method does not set the `length` property of curried functions.
+ * **Note:** This method does not set the "length" property of curried functions.
  *
  * @static
  * @memberOf _

function/debounce.js

@@ -8,12 +8,13 @@ var FUNC_ERROR_TEXT = 'Expected a function';
 var nativeMax = Math.max;
 
 /**
- * Creates a function that delays invoking `func` until after `wait` milliseconds
- * have elapsed since the last time it was invoked. The created function comes
- * with a `cancel` method to cancel delayed invocations. Provide an options
- * object to indicate that `func` should be invoked on the leading and/or
- * trailing edge of the `wait` timeout. Subsequent calls to the debounced
- * function return the result of the last `func` invocation.
+ * Creates a debounced function that delays invoking `func` until after `wait`
+ * milliseconds have elapsed since the last time the debounced function was
+ * invoked. The debounced function comes with a `cancel` method to cancel
+ * delayed invocations. Provide an options object to indicate that `func`
+ * should be invoked on the leading and/or trailing edge of the `wait` timeout.
+ * Subsequent calls to the debounced function return the result of the last
+ * `func` invocation.
  *
  * **Note:** If `leading` and `trailing` options are `true`, `func` is invoked
  * on the trailing edge of the timeout only if the the debounced function is
@@ -89,9 +90,9 @@ function debounce(func, wait, options) {
     var leading = true;
     trailing = false;
   } else if (isObject(options)) {
-    leading = options.leading;
+    leading = !!options.leading;
     maxWait = 'maxWait' in options && nativeMax(+options.maxWait || 0, wait);
-    trailing = 'trailing' in options ? options.trailing : trailing;
+    trailing = 'trailing' in options ? !!options.trailing : trailing;
   }
 
   function cancel() {
@@ -101,41 +102,35 @@ function debounce(func, wait, options) {
     if (maxTimeoutId) {
       clearTimeout(maxTimeoutId);
     }
+    lastCalled = 0;
     maxTimeoutId = timeoutId = trailingCall = undefined;
   }
 
+  function complete(isCalled, id) {
+    if (id) {
+      clearTimeout(id);
+    }
+    maxTimeoutId = timeoutId = trailingCall = undefined;
+    if (isCalled) {
+      lastCalled = now();
+      result = func.apply(thisArg, args);
+      if (!timeoutId && !maxTimeoutId) {
+        args = thisArg = undefined;
+      }
+    }
+  }
+
   function delayed() {
     var remaining = wait - (now() - stamp);
     if (remaining <= 0 || remaining > wait) {
-      if (maxTimeoutId) {
-        clearTimeout(maxTimeoutId);
-      }
-      var isCalled = trailingCall;
-      maxTimeoutId = timeoutId = trailingCall = undefined;
-      if (isCalled) {
-        lastCalled = now();
-        result = func.apply(thisArg, args);
-        if (!timeoutId && !maxTimeoutId) {
-          args = thisArg = null;
-        }
-      }
+      complete(trailingCall, maxTimeoutId);
     } else {
       timeoutId = setTimeout(delayed, remaining);
     }
   }
 
   function maxDelayed() {
-    if (timeoutId) {
-      clearTimeout(timeoutId);
-    }
-    maxTimeoutId = timeoutId = trailingCall = undefined;
-    if (trailing || (maxWait !== wait)) {
-      lastCalled = now();
-      result = func.apply(thisArg, args);
-      if (!timeoutId && !maxTimeoutId) {
-        args = thisArg = null;
-      }
-    }
+    complete(trailing, timeoutId);
   }
 
   function debounced() {
@@ -175,7 +170,7 @@ function debounce(func, wait, options) {
       result = func.apply(thisArg, args);
     }
     if (isCalled && !timeoutId && !maxTimeoutId) {
-      args = thisArg = null;
+      args = thisArg = undefined;
     }
     return result;
   }

function/memoize.js

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

function/modArgs.js

@@ -0,0 +1,58 @@
+import arrayEvery from '../internal/arrayEvery';
+import baseFlatten from '../internal/baseFlatten';
+import baseIsFunction from '../internal/baseIsFunction';
+import restParam from './restParam';
+
+/** Used as the `TypeError` message for "Functions" methods. */
+var FUNC_ERROR_TEXT = 'Expected a function';
+
+/* Native method references for those with the same name as other `lodash` methods. */
+var nativeMin = Math.min;
+
+/**
+ * Creates a function that runs each argument through a corresponding
+ * transform function.
+ *
+ * @static
+ * @memberOf _
+ * @category Function
+ * @param {Function} func The function to wrap.
+ * @param {...(Function|Function[])} [transforms] The functions to transform
+ * arguments, specified as individual functions or arrays of functions.
+ * @returns {Function} Returns the new function.
+ * @example
+ *
+ * function doubled(n) {
+ *   return n * 2;
+ * }
+ *
+ * function square(n) {
+ *   return n * n;
+ * }
+ *
+ * var modded = _.modArgs(function(x, y) {
+ *   return [x, y];
+ * }, square, doubled);
+ *
+ * modded(1, 2);
+ * // => [1, 4]
+ *
+ * modded(5, 10);
+ * // => [25, 20]
+ */
+var modArgs = restParam(function(func, transforms) {
+  transforms = baseFlatten(transforms);
+  if (typeof func != 'function' || !arrayEvery(transforms, baseIsFunction)) {
+    throw new TypeError(FUNC_ERROR_TEXT);
+  }
+  var length = transforms.length;
+  return restParam(function(args) {
+    var index = nativeMin(args.length, length);
+    while (index--) {
+      args[index] = transforms[index](args[index]);
+    }
+    return func.apply(this, args);
+  });
+});
+
+export default modArgs;

function/once.js

@@ -18,7 +18,7 @@ import before from './before';
  * // `initialize` invokes `createApplication` once
  */
 function once(func) {
-  return before(func, 2);
+  return before(2, func);
 }
 
 export default once;

function/partial.js

@@ -11,7 +11,7 @@ var PARTIAL_FLAG = 32;
  * The `_.partial.placeholder` value, which defaults to `_` in monolithic
  * builds, may be used as a placeholder for partially applied arguments.
  *
- * **Note:** This method does not set the `length` property of partially
+ * **Note:** This method does not set the "length" property of partially
  * applied functions.
  *
  * @static

function/partialRight.js

@@ -10,7 +10,7 @@ var PARTIAL_RIGHT_FLAG = 64;
  * The `_.partialRight.placeholder` value, which defaults to `_` in monolithic
  * builds, may be used as a placeholder for partially applied arguments.
  *
- * **Note:** This method does not set the `length` property of partially
+ * **Note:** This method does not set the "length" property of partially
  * applied functions.
  *
  * @static

function/rearg.js

@@ -34,7 +34,7 @@ var REARG_FLAG = 256;
  * // => [3, 6, 9]
  */
 var rearg = restParam(function(func, indexes) {
-  return createWrapper(func, REARG_FLAG, null, null, null, baseFlatten(indexes));
+  return createWrapper(func, REARG_FLAG, undefined, undefined, undefined, baseFlatten(indexes));
 });
 
 export default rearg;

function/restParam.js

@@ -30,7 +30,7 @@ function restParam(func, start) {
   if (typeof func != 'function') {
     throw new TypeError(FUNC_ERROR_TEXT);
   }
-  start = nativeMax(typeof start == 'undefined' ? (func.length - 1) : (+start || 0), 0);
+  start = nativeMax(start === undefined ? (func.length - 1) : (+start || 0), 0);
   return function() {
     var args = arguments,
         index = -1,

function/throttle.js

@@ -4,20 +4,13 @@ import isObject from '../lang/isObject';
 /** Used as the `TypeError` message for "Functions" methods. */
 var FUNC_ERROR_TEXT = 'Expected a function';
 
-/** Used as an internal `_.debounce` options object by `_.throttle`. */
-var debounceOptions = {
-  'leading': false,
-  'maxWait': 0,
-  'trailing': false
-};
-
 /**
- * Creates a function that only invokes `func` at most once per every `wait`
- * milliseconds. The created function comes with a `cancel` method to cancel
- * delayed invocations. Provide an options object to indicate that `func`
- * should be invoked on the leading and/or trailing edge of the `wait` timeout.
- * Subsequent calls to the throttled function return the result of the last
- * `func` call.
+ * Creates a throttled function that only invokes `func` at most once per
+ * every `wait` milliseconds. The throttled function comes with a `cancel`
+ * method to cancel delayed invocations. Provide an options object to indicate
+ * that `func` should be invoked on the leading and/or trailing edge of the
+ * `wait` timeout. Subsequent calls to the throttled function return the
+ * result of the last `func` call.
  *
  * **Note:** If `leading` and `trailing` options are `true`, `func` is invoked
  * on the trailing edge of the timeout only if the the throttled function is
@@ -63,10 +56,7 @@ function throttle(func, wait, options) {
     leading = 'leading' in options ? !!options.leading : leading;
     trailing = 'trailing' in options ? !!options.trailing : trailing;
   }
-  debounceOptions.leading = leading;
-  debounceOptions.maxWait = +wait;
-  debounceOptions.trailing = trailing;
-  return debounce(func, wait, debounceOptions);
+  return debounce(func, wait, { 'leading': leading, 'maxWait': +wait, 'trailing': trailing });
 }
 
 export default throttle;

function/wrap.js

@@ -27,7 +27,7 @@ var PARTIAL_FLAG = 32;
  */
 function wrap(value, wrapper) {
   wrapper = wrapper == null ? identity : wrapper;
-  return createWrapper(wrapper, PARTIAL_FLAG, null, [value], []);
+  return createWrapper(wrapper, PARTIAL_FLAG, undefined, [value], []);
 }
 
 export default wrap;

internal/LazyWrapper.js

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

internal/SetCache.js

@@ -1,12 +1,12 @@
 import cachePush from './cachePush';
-import isNative from '../lang/isNative';
+import getNative from './getNative';
 import root from './root';
 
 /** Native method references. */
-var Set = isNative(Set = root.Set) && Set;
+var Set = getNative(root, 'Set');
 
 /* Native method references for those with the same name as other `lodash` methods. */
-var nativeCreate = isNative(nativeCreate = Object.create) && nativeCreate;
+var nativeCreate = getNative(Object, 'create');
 
 /**
  *

internal/arrayConcat.js

@@ -0,0 +1,25 @@
+/**
+ * Creates a new array joining `array` with `other`.
+ *
+ * @private
+ * @param {Array} array The array to join.
+ * @param {Array} other The other array to join.
+ * @returns {Array} Returns the new concatenated array.
+ */
+function arrayConcat(array, other) {
+  var index = -1,
+      length = array.length,
+      othIndex = -1,
+      othLength = other.length,
+      result = Array(length + othLength);
+
+  while (++index < length) {
+    result[index] = array[index];
+  }
+  while (++othIndex < othLength) {
+    result[index++] = other[othIndex];
+  }
+  return result;
+}
+
+export default arrayConcat;

internal/arrayExtremum.js

@@ -0,0 +1,30 @@
+/**
+ * A specialized version of `baseExtremum` for arrays which invokes `iteratee`
+ * with one argument: (value).
+ *
+ * @private
+ * @param {Array} array The array to iterate over.
+ * @param {Function} iteratee The function invoked per iteration.
+ * @param {Function} comparator The function used to compare values.
+ * @param {*} exValue The initial extremum value.
+ * @returns {*} Returns the extremum value.
+ */
+function arrayExtremum(array, iteratee, comparator, exValue) {
+  var index = -1,
+      length = array.length,
+      computed = exValue,
+      result = computed;
+
+  while (++index < length) {
+    var value = array[index],
+        current = +iteratee(value);
+
+    if (comparator(current, computed)) {
+      computed = current;
+      result = value;
+    }
+  }
+  return result;
+}
+
+export default arrayExtremum;

internal/arrayMax.js

@@ -1,25 +0,0 @@
-/** Used as references for `-Infinity` and `Infinity`. */
-var NEGATIVE_INFINITY = Number.NEGATIVE_INFINITY;
-
-/**
- * A specialized version of `_.max` for arrays without support for iteratees.
- *
- * @private
- * @param {Array} array The array to iterate over.
- * @returns {*} Returns the maximum value.
- */
-function arrayMax(array) {
-  var index = -1,
-      length = array.length,
-      result = NEGATIVE_INFINITY;
-
-  while (++index < length) {
-    var value = array[index];
-    if (value > result) {
-      result = value;
-    }
-  }
-  return result;
-}
-
-export default arrayMax;

internal/arrayMin.js

@@ -1,25 +0,0 @@
-/** Used as references for `-Infinity` and `Infinity`. */
-var POSITIVE_INFINITY = Number.POSITIVE_INFINITY;
-
-/**
- * A specialized version of `_.min` for arrays without support for iteratees.
- *
- * @private
- * @param {Array} array The array to iterate over.
- * @returns {*} Returns the minimum value.
- */
-function arrayMin(array) {
-  var index = -1,
-      length = array.length,
-      result = POSITIVE_INFINITY;
-
-  while (++index < length) {
-    var value = array[index];
-    if (value < result) {
-      result = value;
-    }
-  }
-  return result;
-}
-
-export default arrayMin;

internal/arrayPush.js

@@ -0,0 +1,20 @@
+/**
+ * Appends the elements of `values` to `array`.
+ *
+ * @private
+ * @param {Array} array The array to modify.
+ * @param {Array} values The values to append.
+ * @returns {Array} Returns `array`.
+ */
+function arrayPush(array, values) {
+  var index = -1,
+      length = values.length,
+      offset = array.length;
+
+  while (++index < length) {
+    array[offset + index] = values[index];
+  }
+  return array;
+}
+
+export default arrayPush;

internal/arraySum.js

@@ -1,16 +1,18 @@
 /**
- * A specialized version of `_.sum` for arrays without support for iteratees.
+ * A specialized version of `_.sum` for arrays without support for callback
+ * shorthands and `this` binding..
  *
  * @private
  * @param {Array} array The array to iterate over.
+ * @param {Function} iteratee The function invoked per iteration.
  * @returns {number} Returns the sum.
  */
-function arraySum(array) {
+function arraySum(array, iteratee) {
   var length = array.length,
       result = 0;
 
   while (length--) {
-    result += +array[length] || 0;
+    result += +iteratee(array[length]) || 0;
   }
   return result;
 }

internal/assignDefaults.js

@@ -7,7 +7,7 @@
  * @returns {*} Returns the value to assign to the destination object.
  */
 function assignDefaults(objectValue, sourceValue) {
-  return typeof objectValue == 'undefined' ? sourceValue : objectValue;
+  return objectValue === undefined ? sourceValue : objectValue;
 }
 
 export default assignDefaults;

internal/assignOwnDefaults.js

@@ -7,7 +7,7 @@ var hasOwnProperty = objectProto.hasOwnProperty;
 /**
  * Used by `_.template` to customize its `_.assign` use.
  *
- * **Note:** This method is like `assignDefaults` except that it ignores
+ * **Note:** This function is like `assignDefaults` except that it ignores
  * inherited property values when checking if a property is `undefined`.
  *
  * @private
@@ -18,7 +18,7 @@ var hasOwnProperty = objectProto.hasOwnProperty;
  * @returns {*} Returns the value to assign to the destination object.
  */
 function assignOwnDefaults(objectValue, sourceValue, key, object) {
-  return (typeof objectValue == 'undefined' || !hasOwnProperty.call(object, key))
+  return (objectValue === undefined || !hasOwnProperty.call(object, key))
     ? sourceValue
     : objectValue;
 }

internal/assignWith.js

@@ -0,0 +1,32 @@
+import keys from '../object/keys';
+
+/**
+ * A specialized version of `_.assign` for customizing assigned values without
+ * support for argument juggling, multiple sources, and `this` binding `customizer`
+ * functions.
+ *
+ * @private
+ * @param {Object} object The destination object.
+ * @param {Object} source The source object.
+ * @param {Function} customizer The function to customize assigned values.
+ * @returns {Object} Returns `object`.
+ */
+function assignWith(object, source, customizer) {
+  var index = -1,
+      props = keys(source),
+      length = props.length;
+
+  while (++index < length) {
+    var key = props[index],
+        value = object[key],
+        result = customizer(value, source[key], key, object, source);
+
+    if ((result === result ? (result !== value) : (value === value)) ||
+        (value === undefined && !(key in object))) {
+      object[key] = result;
+    }
+  }
+  return object;
+}
+
+export default assignWith;

internal/baseAssign.js

@@ -3,33 +3,17 @@ import keys from '../object/keys';
 
 /**
  * The base implementation of `_.assign` without support for argument juggling,
- * multiple sources, and `this` binding `customizer` functions.
+ * multiple sources, and `customizer` functions.
  *
  * @private
  * @param {Object} object The destination object.
  * @param {Object} source The source object.
- * @param {Function} [customizer] The function to customize assigning values.
- * @returns {Object} Returns the destination object.
+ * @returns {Object} Returns `object`.
  */
-function baseAssign(object, source, customizer) {
-  var props = keys(source);
-  if (!customizer) {
-    return baseCopy(source, object, props);
-  }
-  var index = -1,
-      length = props.length;
-
-  while (++index < length) {
-    var key = props[index],
-        value = object[key],
-        result = customizer(value, source[key], key, object, source);
-
-    if ((result === result ? (result !== value) : (value === value)) ||
-        (typeof value == 'undefined' && !(key in object))) {
-      object[key] = result;
-    }
-  }
-  return object;
+function baseAssign(object, source) {
+  return source == null
+    ? object
+    : baseCopy(source, keys(source), object);
 }
 
 export default baseAssign;

internal/baseAt.js

@@ -1,29 +1,29 @@
+import isArrayLike from './isArrayLike';
 import isIndex from './isIndex';
-import isLength from './isLength';
 
 /**
- * The base implementation of `_.at` without support for strings and individual
- * key arguments.
+ * The base implementation of `_.at` without support for string collections
+ * and individual key arguments.
  *
  * @private
  * @param {Array|Object} collection The collection to iterate over.
- * @param {number[]|string[]} [props] The property names or indexes of elements to pick.
+ * @param {number[]|string[]} props The property names or indexes of elements to pick.
  * @returns {Array} Returns the new array of picked elements.
  */
 function baseAt(collection, props) {
   var index = -1,
-      length = collection.length,
-      isArr = isLength(length),
+      isNil = collection == null,
+      isArr = !isNil && isArrayLike(collection),
+      length = isArr ? collection.length : 0,
       propsLength = props.length,
       result = Array(propsLength);
 
   while(++index < propsLength) {
     var key = props[index];
     if (isArr) {
-      key = parseFloat(key);
       result[index] = isIndex(key, length) ? collection[key] : undefined;
     } else {
-      result[index] = collection[key];
+      result[index] = isNil ? undefined : collection[key];
     }
   }
   return result;

internal/baseCallback.js

@@ -1,8 +1,8 @@
 import baseMatches from './baseMatches';
 import baseMatchesProperty from './baseMatchesProperty';
-import baseProperty from './baseProperty';
 import bindCallback from './bindCallback';
 import identity from '../utility/identity';
+import property from '../utility/property';
 
 /**
  * The base implementation of `_.callback` which supports specifying the
@@ -17,7 +17,7 @@ import identity from '../utility/identity';
 function baseCallback(func, thisArg, argCount) {
   var type = typeof func;
   if (type == 'function') {
-    return typeof thisArg == 'undefined'
+    return thisArg === undefined
       ? func
       : bindCallback(func, thisArg, argCount);
   }
@@ -27,9 +27,9 @@ function baseCallback(func, thisArg, argCount) {
   if (type == 'object') {
     return baseMatches(func);
   }
-  return typeof thisArg == 'undefined'
-    ? baseProperty(func + '')
-    : baseMatchesProperty(func + '', thisArg);
+  return thisArg === undefined
+    ? property(func)
+    : baseMatchesProperty(func, thisArg);
 }
 
 export default baseCallback;

internal/baseClone.js

@@ -1,13 +1,12 @@
 import arrayCopy from './arrayCopy';
 import arrayEach from './arrayEach';
-import baseCopy from './baseCopy';
+import baseAssign from './baseAssign';
 import baseForOwn from './baseForOwn';
 import initCloneArray from './initCloneArray';
 import initCloneByTag from './initCloneByTag';
 import initCloneObject from './initCloneObject';
 import isArray from '../lang/isArray';
 import isObject from '../lang/isObject';
-import keys from '../object/keys';
 
 /** `Object#toString` result references. */
 var argsTag = '[object Arguments]',
@@ -54,7 +53,7 @@ cloneableTags[weakMapTag] = false;
 var objectProto = Object.prototype;
 
 /**
- * Used to resolve the [`toStringTag`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.prototype.tostring)
+ * Used to resolve the [`toStringTag`](http://ecma-international.org/ecma-262/6.0/#sec-object.prototype.tostring)
  * of values.
  */
 var objToString = objectProto.toString;
@@ -78,7 +77,7 @@ function baseClone(value, isDeep, customizer, key, object, stackA, stackB) {
   if (customizer) {
     result = object ? customizer(value, key, object) : customizer(value);
   }
-  if (typeof result != 'undefined') {
+  if (result !== undefined) {
     return result;
   }
   if (!isObject(value)) {
@@ -97,7 +96,7 @@ function baseClone(value, isDeep, customizer, key, object, stackA, stackB) {
     if (tag == objectTag || tag == argsTag || (isFunc && !object)) {
       result = initCloneObject(isFunc ? {} : value);
       if (!isDeep) {
-        return baseCopy(value, result, keys(value));
+        return baseAssign(result, value);
       }
     } else {
       return cloneableTags[tag]
@@ -105,7 +104,7 @@ function baseClone(value, isDeep, customizer, key, object, stackA, stackB) {
         : (object ? value : {});
     }
   }
-  // Check for circular references and return corresponding clone.
+  // Check for circular references and return its corresponding clone.
   stackA || (stackA = []);
   stackB || (stackB = []);
 

internal/baseCompareAscending.js

@@ -3,19 +3,28 @@
  * sorts them in ascending order without guaranteeing a stable sort.
  *
  * @private
- * @param {*} value The value to compare to `other`.
- * @param {*} other The value to compare to `value`.
+ * @param {*} value The value to compare.
+ * @param {*} other The other value to compare.
  * @returns {number} Returns the sort order indicator for `value`.
  */
 function baseCompareAscending(value, other) {
   if (value !== other) {
-    var valIsReflexive = value === value,
+    var valIsNull = value === null,
+        valIsUndef = value === undefined,
+        valIsReflexive = value === value;
+
+    var othIsNull = other === null,
+        othIsUndef = other === undefined,
         othIsReflexive = other === other;
 
-    if (value > other || !valIsReflexive || (typeof value == 'undefined' && othIsReflexive)) {
+    if ((value > other && !othIsNull) || !valIsReflexive ||
+        (valIsNull && !othIsUndef && othIsReflexive) ||
+        (valIsUndef && othIsReflexive)) {
       return 1;
     }
-    if (value < other || !othIsReflexive || (typeof other == 'undefined' && valIsReflexive)) {
+    if ((value < other && !valIsNull) || !othIsReflexive ||
+        (othIsNull && !valIsUndef && valIsReflexive) ||
+        (othIsUndef && valIsReflexive)) {
       return -1;
     }
   }

internal/baseCopy.js

@@ -1,17 +1,15 @@
 /**
- * Copies the properties of `source` to `object`.
+ * Copies properties of `source` to `object`.
  *
  * @private
  * @param {Object} source The object to copy properties from.
- * @param {Object} [object={}] The object to copy properties to.
  * @param {Array} props The property names to copy.
+ * @param {Object} [object={}] The object to copy properties to.
  * @returns {Object} Returns `object`.
  */
-function baseCopy(source, object, props) {
-  if (!props) {
-    props = object;
-    object = {};
-  }
+function baseCopy(source, props, object) {
+  object || (object = {});
+
   var index = -1,
       length = props.length;
 

internal/baseCreate.js

@@ -1,5 +1,4 @@
 import isObject from '../lang/isObject';
-import root from './root';
 
 /**
  * The base implementation of `_.create` without support for assigning
@@ -10,14 +9,14 @@ import root from './root';
  * @returns {Object} Returns the new object.
  */
 var baseCreate = (function() {
-  function Object() {}
+  function object() {}
   return function(prototype) {
     if (isObject(prototype)) {
-      Object.prototype = prototype;
-      var result = new Object;
-      Object.prototype = null;
+      object.prototype = prototype;
+      var result = new object;
+      object.prototype = undefined;
     }
-    return result || root.Object();
+    return result || {};
   };
 }());
 

internal/baseDifference.js

@@ -2,6 +2,9 @@ import baseIndexOf from './baseIndexOf';
 import cacheIndexOf from './cacheIndexOf';
 import createCache from './createCache';
 
+/** Used as the size to enable large array optimizations. */
+var LARGE_ARRAY_SIZE = 200;
+
 /**
  * The base implementation of `_.difference` which accepts a single array
  * of values to exclude.
@@ -21,7 +24,7 @@ function baseDifference(array, values) {
   var index = -1,
       indexOf = baseIndexOf,
       isCommon = true,
-      cache = (isCommon && values.length >= 200) ? createCache(values) : null,
+      cache = (isCommon && values.length >= LARGE_ARRAY_SIZE) ? createCache(values) : null,
       valuesLength = values.length;
 
   if (cache) {

internal/baseExtremum.js

@@ -1,30 +1,24 @@
 import baseEach from './baseEach';
 
-/** Used as references for `-Infinity` and `Infinity`. */
-var NEGATIVE_INFINITY = Number.NEGATIVE_INFINITY,
-    POSITIVE_INFINITY = Number.POSITIVE_INFINITY;
-
 /**
  * Gets the extremum value of `collection` invoking `iteratee` for each value
  * in `collection` to generate the criterion by which the value is ranked.
- * The `iteratee` is invoked with three arguments: (value, index, collection).
+ * The `iteratee` is invoked with three arguments: (value, index|key, collection).
  *
  * @private
  * @param {Array|Object|string} collection The collection to iterate over.
  * @param {Function} iteratee The function invoked per iteration.
- * @param {boolean} [isMin] Specify returning the minimum, instead of the
- *  maximum, extremum value.
+ * @param {Function} comparator The function used to compare values.
+ * @param {*} exValue The initial extremum value.
  * @returns {*} Returns the extremum value.
  */
-function extremumBy(collection, iteratee, isMin) {
-  var exValue = isMin ? POSITIVE_INFINITY : NEGATIVE_INFINITY,
-      computed = exValue,
+function baseExtremum(collection, iteratee, comparator, exValue) {
+  var computed = exValue,
       result = computed;
 
   baseEach(collection, function(value, index, collection) {
-    var current = iteratee(value, index, collection);
-    if ((isMin ? (current < computed) : (current > computed)) ||
-        (current === exValue && current === result)) {
+    var current = +iteratee(value, index, collection);
+    if (comparator(current, computed) || (current === exValue && current === result)) {
       computed = current;
       result = value;
     }
@@ -32,4 +26,4 @@ function extremumBy(collection, iteratee, isMin) {
   return result;
 }
 
-export default extremumBy;
+export default baseExtremum;

internal/baseFill.js

@@ -15,7 +15,7 @@ function baseFill(array, value, start, end) {
   if (start < 0) {
     start = -start > length ? 0 : (length + start);
   }
-  end = (typeof end == 'undefined' || end > length) ? length : (+end || 0);
+  end = (end === undefined || end > length) ? length : (+end || 0);
   if (end < 0) {
     end += length;
   }

internal/baseFlatten.js

@@ -1,6 +1,7 @@
+import arrayPush from './arrayPush';
 import isArguments from '../lang/isArguments';
 import isArray from '../lang/isArray';
-import isLength from './isLength';
+import isArrayLike from './isArrayLike';
 import isObjectLike from './isObjectLike';
 
 /**
@@ -9,33 +10,29 @@ import isObjectLike from './isObjectLike';
  *
  * @private
  * @param {Array} array The array to flatten.
- * @param {boolean} isDeep Specify a deep flatten.
- * @param {boolean} isStrict Restrict flattening to arrays and `arguments` objects.
+ * @param {boolean} [isDeep] Specify a deep flatten.
+ * @param {boolean} [isStrict] Restrict flattening to arrays-like objects.
+ * @param {Array} [result=[]] The initial result value.
  * @returns {Array} Returns the new flattened array.
  */
-function baseFlatten(array, isDeep, isStrict) {
+function baseFlatten(array, isDeep, isStrict, result) {
+  result || (result = []);
+
   var index = -1,
-      length = array.length,
-      resIndex = -1,
-      result = [];
+      length = array.length;
 
   while (++index < length) {
     var value = array[index];
-
-    if (isObjectLike(value) && isLength(value.length) && (isArray(value) || isArguments(value))) {
+    if (isObjectLike(value) && isArrayLike(value) &&
+        (isStrict || isArray(value) || isArguments(value))) {
       if (isDeep) {
         // Recursively flatten arrays (susceptible to call stack limits).
-        value = baseFlatten(value, isDeep, isStrict);
-      }
-      var valIndex = -1,
-          valLength = value.length;
-
-      result.length += valLength;
-      while (++valIndex < valLength) {
-        result[++resIndex] = value[valIndex];
+        baseFlatten(value, isDeep, isStrict, result);
+      } else {
+        arrayPush(result, value);
       }
     } else if (!isStrict) {
-      result[++resIndex] = value;
+      result[result.length] = value;
     }
   }
   return result;

internal/baseFor.js

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

internal/baseGet.js

@@ -0,0 +1,29 @@
+import toObject from './toObject';
+
+/**
+ * The base implementation of `get` without support for string paths
+ * and default values.
+ *
+ * @private
+ * @param {Object} object The object to query.
+ * @param {Array} path The path of the property to get.
+ * @param {string} [pathKey] The key representation of path.
+ * @returns {*} Returns the resolved value.
+ */
+function baseGet(object, path, pathKey) {
+  if (object == null) {
+    return;
+  }
+  if (pathKey !== undefined && pathKey in toObject(object)) {
+    path = [pathKey];
+  }
+  var index = 0,
+      length = path.length;
+
+  while (object != null && index < length) {
+    object = object[path[index++]];
+  }
+  return (index && index == length) ? object : undefined;
+}
+
+export default baseGet;

internal/baseIsEqual.js

@@ -1,4 +1,6 @@
 import baseIsEqualDeep from './baseIsEqualDeep';
+import isObject from '../lang/isObject';
+import isObjectLike from './isObjectLike';
 
 /**
  * The base implementation of `_.isEqual` without support for `this` binding
@@ -14,18 +16,10 @@ import baseIsEqualDeep from './baseIsEqualDeep';
  * @returns {boolean} Returns `true` if the values are equivalent, else `false`.
  */
 function baseIsEqual(value, other, customizer, isLoose, stackA, stackB) {
-  // Exit early for identical values.
   if (value === other) {
-    // Treat `+0` vs. `-0` as not equal.
-    return value !== 0 || (1 / value == 1 / other);
+    return true;
   }
-  var valType = typeof value,
-      othType = typeof other;
-
-  // Exit early for unlike primitive values.
-  if ((valType != 'function' && valType != 'object' && othType != 'function' && othType != 'object') ||
-      value == null || other == null) {
-    // Return `false` unless both values are `NaN`.
+  if (value == null || other == null || (!isObject(value) && !isObjectLike(other))) {
     return value !== value && other !== other;
   }
   return baseIsEqualDeep(value, other, baseIsEqual, customizer, isLoose, stackA, stackB);

internal/baseIsEqualDeep.js

@@ -7,7 +7,6 @@ import isTypedArray from '../lang/isTypedArray';
 /** `Object#toString` result references. */
 var argsTag = '[object Arguments]',
     arrayTag = '[object Array]',
-    funcTag = '[object Function]',
     objectTag = '[object Object]';
 
 /** Used for native method references. */
@@ -17,7 +16,7 @@ var objectProto = Object.prototype;
 var hasOwnProperty = objectProto.hasOwnProperty;
 
 /**
- * Used to resolve the [`toStringTag`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.prototype.tostring)
+ * Used to resolve the [`toStringTag`](http://ecma-international.org/ecma-262/6.0/#sec-object.prototype.tostring)
  * of values.
  */
 var objToString = objectProto.toString;
@@ -59,28 +58,24 @@ function baseIsEqualDeep(object, other, equalFunc, customizer, isLoose, stackA,
       othIsArr = isTypedArray(other);
     }
   }
-  var objIsObj = (objTag == objectTag || (isLoose && objTag == funcTag)),
-      othIsObj = (othTag == objectTag || (isLoose && othTag == funcTag)),
+  var objIsObj = objTag == objectTag,
+      othIsObj = othTag == objectTag,
       isSameTag = objTag == othTag;
 
   if (isSameTag && !(objIsArr || objIsObj)) {
     return equalByTag(object, other, objTag);
   }
-  if (isLoose) {
-    if (!isSameTag && !(objIsObj && othIsObj)) {
-      return false;
-    }
-  } else {
-    var valWrapped = objIsObj && hasOwnProperty.call(object, '__wrapped__'),
-        othWrapped = othIsObj && hasOwnProperty.call(other, '__wrapped__');
+  if (!isLoose) {
+    var objIsWrapped = objIsObj && hasOwnProperty.call(object, '__wrapped__'),
+        othIsWrapped = othIsObj && hasOwnProperty.call(other, '__wrapped__');
 
-    if (valWrapped || othWrapped) {
-      return equalFunc(valWrapped ? object.value() : object, othWrapped ? other.value() : other, customizer, isLoose, stackA, stackB);
-    }
-    if (!isSameTag) {
-      return false;
+    if (objIsWrapped || othIsWrapped) {
+      return equalFunc(objIsWrapped ? object.value() : object, othIsWrapped ? other.value() : other, customizer, isLoose, stackA, stackB);
     }
   }
+  if (!isSameTag) {
+    return false;
+  }
   // Assume cyclic values are equal.
   // For more information on detecting circular references see https://es5.github.io/#JO.
   stackA || (stackA = []);

internal/baseIsMatch.js

@@ -1,4 +1,5 @@
 import baseIsEqual from './baseIsEqual';
+import toObject from './toObject';
 
 /**
  * The base implementation of `_.isMatch` without support for callback
@@ -6,41 +7,43 @@ import baseIsEqual from './baseIsEqual';
  *
  * @private
  * @param {Object} object The object to inspect.
- * @param {Array} props The source property names to match.
- * @param {Array} values The source values to match.
- * @param {Array} strictCompareFlags Strict comparison flags for source values.
+ * @param {Array} matchData The propery names, values, and compare flags to match.
  * @param {Function} [customizer] The function to customize comparing objects.
  * @returns {boolean} Returns `true` if `object` is a match, else `false`.
  */
-function baseIsMatch(object, props, values, strictCompareFlags, customizer) {
-  var index = -1,
-      length = props.length,
+function baseIsMatch(object, matchData, customizer) {
+  var index = matchData.length,
+      length = index,
       noCustomizer = !customizer;
 
-  while (++index < length) {
-    if ((noCustomizer && strictCompareFlags[index])
-          ? values[index] !== object[props[index]]
-          : !(props[index] in object)
+  if (object == null) {
+    return !length;
+  }
+  object = toObject(object);
+  while (index--) {
+    var data = matchData[index];
+    if ((noCustomizer && data[2])
+          ? data[1] !== object[data[0]]
+          : !(data[0] in object)
         ) {
       return false;
     }
   }
-  index = -1;
   while (++index < length) {
-    var key = props[index],
+    data = matchData[index];
+    var key = data[0],
         objValue = object[key],
-        srcValue = values[index];
+        srcValue = data[1];
 
-    if (noCustomizer && strictCompareFlags[index]) {
-      var result = typeof objValue != 'undefined' || (key in object);
-    } else {
-      result = customizer ? customizer(objValue, srcValue, key) : undefined;
-      if (typeof result == 'undefined') {
-        result = baseIsEqual(srcValue, objValue, customizer, true);
+    if (noCustomizer && data[2]) {
+      if (objValue === undefined && !(key in object)) {
+        return false;
+      }
+    } else {
+      var result = customizer ? customizer(objValue, srcValue, key) : undefined;
+      if (!(result === undefined ? baseIsEqual(srcValue, objValue, customizer, true) : result)) {
+        return false;
       }
-    }
-    if (!result) {
-      return false;
     }
   }
   return true;

internal/baseMap.js

@@ -1,4 +1,5 @@
 import baseEach from './baseEach';
+import isArrayLike from './isArrayLike';
 
 /**
  * The base implementation of `_.map` without support for callback shorthands
@@ -10,9 +11,11 @@ import baseEach from './baseEach';
  * @returns {Array} Returns the new mapped array.
  */
 function baseMap(collection, iteratee) {
-  var result = [];
+  var index = -1,
+      result = isArrayLike(collection) ? Array(collection.length) : [];
+
   baseEach(collection, function(value, key, collection) {
-    result.push(iteratee(value, key, collection));
+    result[++index] = iteratee(value, key, collection);
   });
   return result;
 }

internal/baseMatches.js

@@ -1,7 +1,5 @@
 import baseIsMatch from './baseIsMatch';
-import constant from '../utility/constant';
-import isStrictComparable from './isStrictComparable';
-import keys from '../object/keys';
+import getMatchData from './getMatchData';
 import toObject from './toObject';
 
 /**
@@ -12,33 +10,20 @@ import toObject from './toObject';
  * @returns {Function} Returns the new function.
  */
 function baseMatches(source) {
-  var props = keys(source),
-      length = props.length;
+  var matchData = getMatchData(source);
+  if (matchData.length == 1 && matchData[0][2]) {
+    var key = matchData[0][0],
+        value = matchData[0][1];
 
-  if (!length) {
-    return constant(true);
-  }
-  if (length == 1) {
-    var key = props[0],
-        value = source[key];
-
-    if (isStrictComparable(value)) {
-      return function(object) {
-        return object != null && object[key] === value &&
-          (typeof value != 'undefined' || (key in toObject(object)));
-      };
-    }
-  }
-  var values = Array(length),
-      strictCompareFlags = Array(length);
-
-  while (length--) {
-    value = source[props[length]];
-    values[length] = value;
-    strictCompareFlags[length] = isStrictComparable(value);
+    return function(object) {
+      if (object == null) {
+        return false;
+      }
+      return object[key] === value && (value !== undefined || (key in toObject(object)));
+    };
   }
   return function(object) {
-    return object != null && baseIsMatch(toObject(object), props, values, strictCompareFlags);
+    return baseIsMatch(object, matchData);
   };
 }
 

internal/baseMatchesProperty.js

@@ -1,25 +1,44 @@
+import baseGet from './baseGet';
 import baseIsEqual from './baseIsEqual';
+import baseSlice from './baseSlice';
+import isArray from '../lang/isArray';
+import isKey from './isKey';
 import isStrictComparable from './isStrictComparable';
+import last from '../array/last';
 import toObject from './toObject';
+import toPath from './toPath';
 
 /**
- * The base implementation of `_.matchesProperty` which does not coerce `key`
- * to a string.
+ * The base implementation of `_.matchesProperty` which does not clone `srcValue`.
  *
  * @private
- * @param {string} key The key of the property to get.
- * @param {*} value The value to compare.
+ * @param {string} path The path of the property to get.
+ * @param {*} srcValue The value to compare.
  * @returns {Function} Returns the new function.
  */
-function baseMatchesProperty(key, value) {
-  if (isStrictComparable(value)) {
-    return function(object) {
-      return object != null && object[key] === value &&
-        (typeof value != 'undefined' || (key in toObject(object)));
-    };
-  }
+function baseMatchesProperty(path, srcValue) {
+  var isArr = isArray(path),
+      isCommon = isKey(path) && isStrictComparable(srcValue),
+      pathKey = (path + '');
+
+  path = toPath(path);
   return function(object) {
-    return object != null && baseIsEqual(value, object[key], null, true);
+    if (object == null) {
+      return false;
+    }
+    var key = pathKey;
+    object = toObject(object);
+    if ((isArr || !isCommon) && !(key in object)) {
+      object = path.length == 1 ? object : baseGet(object, baseSlice(path, 0, -1));
+      if (object == null) {
+        return false;
+      }
+      key = last(path);
+      object = toObject(object);
+    }
+    return object[key] === srcValue
+      ? (srcValue !== undefined || (key in object))
+      : baseIsEqual(srcValue, object[key], undefined, true);
   };
 }
 

internal/baseMerge.js

@@ -1,11 +1,11 @@
 import arrayEach from './arrayEach';
-import baseForOwn from './baseForOwn';
 import baseMergeDeep from './baseMergeDeep';
 import isArray from '../lang/isArray';
-import isLength from './isLength';
+import isArrayLike from './isArrayLike';
 import isObject from '../lang/isObject';
 import isObjectLike from './isObjectLike';
 import isTypedArray from '../lang/isTypedArray';
+import keys from '../object/keys';
 
 /**
  * The base implementation of `_.merge` without support for argument juggling,
@@ -14,32 +14,40 @@ import isTypedArray from '../lang/isTypedArray';
  * @private
  * @param {Object} object The destination object.
  * @param {Object} source The source object.
- * @param {Function} [customizer] The function to customize merging properties.
+ * @param {Function} [customizer] The function to customize merged values.
  * @param {Array} [stackA=[]] Tracks traversed source objects.
  * @param {Array} [stackB=[]] Associates values with source counterparts.
- * @returns {Object} Returns the destination object.
+ * @returns {Object} Returns `object`.
  */
 function baseMerge(object, source, customizer, stackA, stackB) {
   if (!isObject(object)) {
     return object;
   }
-  var isSrcArr = isLength(source.length) && (isArray(source) || isTypedArray(source));
-  (isSrcArr ? arrayEach : baseForOwn)(source, function(srcValue, key, source) {
+  var isSrcArr = isArrayLike(source) && (isArray(source) || isTypedArray(source)),
+      props = isSrcArr ? undefined : keys(source);
+
+  arrayEach(props || source, function(srcValue, key) {
+    if (props) {
+      key = srcValue;
+      srcValue = source[key];
+    }
     if (isObjectLike(srcValue)) {
       stackA || (stackA = []);
       stackB || (stackB = []);
-      return baseMergeDeep(object, source, key, baseMerge, customizer, stackA, stackB);
+      baseMergeDeep(object, source, key, baseMerge, customizer, stackA, stackB);
     }
-    var value = object[key],
-        result = customizer ? customizer(value, srcValue, key, object, source) : undefined,
-        isCommon = typeof result == 'undefined';
+    else {
+      var value = object[key],
+          result = customizer ? customizer(value, srcValue, key, object, source) : undefined,
+          isCommon = result === undefined;
 
-    if (isCommon) {
-      result = srcValue;
-    }
-    if ((isSrcArr || typeof result != 'undefined') &&
-        (isCommon || (result === result ? (result !== value) : (value === value)))) {
-      object[key] = result;
+      if (isCommon) {
+        result = srcValue;
+      }
+      if ((result !== undefined || (isSrcArr && !(key in object))) &&
+          (isCommon || (result === result ? (result !== value) : (value === value)))) {
+        object[key] = result;
+      }
     }
   });
   return object;

internal/baseMergeDeep.js

@@ -1,7 +1,7 @@
 import arrayCopy from './arrayCopy';
 import isArguments from '../lang/isArguments';
 import isArray from '../lang/isArray';
-import isLength from './isLength';
+import isArrayLike from './isArrayLike';
 import isPlainObject from '../lang/isPlainObject';
 import isTypedArray from '../lang/isTypedArray';
 import toPlainObject from '../lang/toPlainObject';
@@ -16,7 +16,7 @@ import toPlainObject from '../lang/toPlainObject';
  * @param {Object} source The source object.
  * @param {string} key The key of the value to merge.
  * @param {Function} mergeFunc The function to merge values.
- * @param {Function} [customizer] The function to customize merging properties.
+ * @param {Function} [customizer] The function to customize merged values.
  * @param {Array} [stackA=[]] Tracks traversed source objects.
  * @param {Array} [stackB=[]] Associates values with source counterparts.
  * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
@@ -33,14 +33,14 @@ function baseMergeDeep(object, source, key, mergeFunc, customizer, stackA, stack
   }
   var value = object[key],
       result = customizer ? customizer(value, srcValue, key, object, source) : undefined,
-      isCommon = typeof result == 'undefined';
+      isCommon = result === undefined;
 
   if (isCommon) {
     result = srcValue;
-    if (isLength(srcValue.length) && (isArray(srcValue) || isTypedArray(srcValue))) {
+    if (isArrayLike(srcValue) && (isArray(srcValue) || isTypedArray(srcValue))) {
       result = isArray(value)
         ? value
-        : ((value && value.length) ? arrayCopy(value) : []);
+        : (isArrayLike(value) ? arrayCopy(value) : []);
     }
     else if (isPlainObject(srcValue) || isArguments(srcValue)) {
       result = isArguments(value)

internal/baseProperty.js

@@ -1,5 +1,5 @@
 /**
- * The base implementation of `_.property` which does not coerce `key` to a string.
+ * The base implementation of `_.property` without support for deep paths.
  *
  * @private
  * @param {string} key The key of the property to get.

internal/basePropertyDeep.js

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

internal/basePullAt.js

@@ -0,0 +1,30 @@
+import isIndex from './isIndex';
+
+/** Used for native method references. */
+var arrayProto = Array.prototype;
+
+/** Native method references. */
+var splice = arrayProto.splice;
+
+/**
+ * The base implementation of `_.pullAt` without support for individual
+ * index arguments and capturing the removed elements.
+ *
+ * @private
+ * @param {Array} array The array to modify.
+ * @param {number[]} indexes The indexes of elements to remove.
+ * @returns {Array} Returns `array`.
+ */
+function basePullAt(array, indexes) {
+  var length = array ? indexes.length : 0;
+  while (length--) {
+    var index = indexes[length];
+    if (index != previous && isIndex(index)) {
+      var previous = index;
+      splice.call(array, index, 1);
+    }
+  }
+  return array;
+}
+
+export default basePullAt;

internal/baseRandom.js

@@ -1,8 +1,6 @@
-/** Native method references. */
-var floor = Math.floor;
-
 /* Native method references for those with the same name as other `lodash` methods. */
-var nativeRandom = Math.random;
+var nativeFloor = Math.floor,
+    nativeRandom = Math.random;
 
 /**
  * The base implementation of `_.random` without support for argument juggling
@@ -14,7 +12,7 @@ var nativeRandom = Math.random;
  * @returns {number} Returns the random number.
  */
 function baseRandom(min, max) {
-  return min + floor(nativeRandom() * (max - min + 1));
+  return min + nativeFloor(nativeRandom() * (max - min + 1));
 }
 
 export default baseRandom;

internal/baseSlice.js

@@ -15,7 +15,7 @@ function baseSlice(array, start, end) {
   if (start < 0) {
     start = -start > length ? 0 : (length + start);
   }
-  end = (typeof end == 'undefined' || end > length) ? length : (+end || 0);
+  end = (end === undefined || end > length) ? length : (+end || 0);
   if (end < 0) {
     end += length;
   }

internal/baseSortByOrder.js

@@ -1,30 +1,26 @@
-import baseEach from './baseEach';
+import arrayMap from './arrayMap';
+import baseCallback from './baseCallback';
+import baseMap from './baseMap';
 import baseSortBy from './baseSortBy';
 import compareMultiple from './compareMultiple';
-import isLength from './isLength';
 
 /**
  * The base implementation of `_.sortByOrder` without param guards.
  *
  * @private
  * @param {Array|Object|string} collection The collection to iterate over.
- * @param {string[]} props The property names to sort by.
- * @param {boolean[]} orders The sort orders of `props`.
+ * @param {Function[]|Object[]|string[]} iteratees The iteratees to sort by.
+ * @param {boolean[]} orders The sort orders of `iteratees`.
  * @returns {Array} Returns the new sorted array.
  */
-function baseSortByOrder(collection, props, orders) {
-  var index = -1,
-      length = collection.length,
-      result = isLength(length) ? Array(length) : [];
+function baseSortByOrder(collection, iteratees, orders) {
+  var index = -1;
 
-  baseEach(collection, function(value) {
-    var length = props.length,
-        criteria = Array(length);
+  iteratees = arrayMap(iteratees, function(iteratee) { return baseCallback(iteratee); });
 
-    while (length--) {
-      criteria[length] = value == null ? undefined : value[props[length]];
-    }
-    result[++index] = { 'criteria': criteria, 'index': index, 'value': value };
+  var result = baseMap(collection, function(value) {
+    var criteria = arrayMap(iteratees, function(iteratee) { return iteratee(value); });
+    return { 'criteria': criteria, 'index': ++index, 'value': value };
   });
 
   return baseSortBy(result, function(object, other) {

internal/baseToString.js

@@ -1,5 +1,5 @@
 /**
- * Converts `value` to a string if it is not one. An empty string is returned
+ * Converts `value` to a string if it's not one. An empty string is returned
  * for `null` or `undefined` values.
  *
  * @private
@@ -7,9 +7,6 @@
  * @returns {string} Returns the string.
  */
 function baseToString(value) {
-  if (typeof value == 'string') {
-    return value;
-  }
   return value == null ? '' : (value + '');
 }