Bump to v3.10.0.

README.md

@@ -1,4 +1,4 @@
-# lodash-es v3.9.3
+# 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/3.9.3-es) for more details.
+See the [package source](https://github.com/lodash/lodash/tree/3.10.0-es) for more details.

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

@@ -1,11 +1,12 @@
 import baseDifference from '../internal/baseDifference';
 import baseFlatten from '../internal/baseFlatten';
 import isArrayLike from '../internal/isArrayLike';
+import isObjectLike from '../internal/isObjectLike';
 import restParam from '../function/restParam';
 
 /**
  * Creates an array of unique `array` values not included in the other
- * provided arrays using [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
+ * provided arrays using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
  * for equality comparisons.
  *
  * @static
@@ -20,7 +21,7 @@ import restParam from '../function/restParam';
  * // => [1, 3]
  */
 var difference = restParam(function(array, values) {
-  return isArrayLike(array)
+  return (isObjectLike(array) && isArrayLike(array))
     ? baseDifference(array, baseFlatten(values, false, true))
     : [];
 });

array/indexOf.js

@@ -6,7 +6,7 @@ var nativeMax = Math.max;
 
 /**
  * Gets the index at which the first occurrence of `value` is found in `array`
- * using [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
+ * 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.
@@ -40,10 +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

@@ -6,7 +6,7 @@ import restParam from '../function/restParam';
 
 /**
  * Creates an array of unique values that are included in all of the provided
- * arrays using [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
+ * arrays using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
  * for equality comparisons.
  *
  * @static

array/pull.js

@@ -8,7 +8,7 @@ var splice = arrayProto.splice;
 
 /**
  * Removes all provided values from `array` using
- * [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
+ * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
  * for equality comparisons.
  *
  * **Note:** Unlike `_.without`, this method mutates `array`.

array/union.js

@@ -4,7 +4,7 @@ import restParam from '../function/restParam';
 
 /**
  * Creates an array of unique values, in order, from all of the provided arrays
- * using [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
+ * using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
  * for equality comparisons.
  *
  * @static

array/uniq.js

@@ -5,7 +5,7 @@ import sortedUniq from '../internal/sortedUniq';
 
 /**
  * Creates a duplicate-free version of an array, using
- * [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
+ * [`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
@@ -59,7 +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/without.js

@@ -4,7 +4,7 @@ import restParam from '../function/restParam';
 
 /**
  * Creates an array excluding all provided values using
- * [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
+ * [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
  * for equality comparisons.
  *
  * @static

array/xor.js

@@ -1,3 +1,4 @@
+import arrayPush from '../internal/arrayPush';
 import baseDifference from '../internal/baseDifference';
 import baseUniq from '../internal/baseUniq';
 import isArrayLike from '../internal/isArrayLike';
@@ -24,7 +25,7 @@ function xor() {
     var array = arguments[index];
     if (isArrayLike(array)) {
       var result = result
-        ? baseDifference(result, array).concat(baseDifference(array, result))
+        ? arrayPush(baseDifference(result, array), baseDifference(array, result))
         : array;
     }
   }

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.
@@ -45,36 +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`, `mapKeys`, `mapValues`, `matches`, `matchesProperty`,
- * `memoize`, `merge`, `method`, `methodOf`, `mixin`, `negate`, `omit`, `once`,
- * `pairs`, `partial`, `partialRight`, `partition`, `pick`, `plant`, `pluck`,
- * `property`, `propertyOf`, `pull`, `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`
+ * `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`, `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`, `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`,
- * `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.

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/every.js

@@ -55,7 +55,7 @@ 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' || thisArg !== undefined) {
     predicate = baseCallback(predicate, thisArg, 3);

collection/includes.js

@@ -11,7 +11,7 @@ var nativeMax = Math.max;
 
 /**
  * Checks if `value` is in `collection` using
- * [`SameValueZero`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-samevaluezero)
+ * [`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`.
  *
@@ -44,17 +44,14 @@ function includes(collection, target, fromIndex, guard) {
     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

@@ -33,7 +33,7 @@ var invoke = restParam(function(collection, path, args) {
       result = isArrayLike(collection) ? Array(collection.length) : [];
 
   baseEach(collection, function(value) {
-    var func = isFunc ? path : ((isProp && value != null) ? value[path] : null);
+    var func = isFunc ? path : ((isProp && value != null) ? value[path] : undefined);
     result[++index] = func ? func.apply(value, args) : invokePath(value, path, args);
   });
   return result;

collection/reduce.js

@@ -14,7 +14,8 @@ import createReduce from '../internal/createReduce';
  * `_.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 _

collection/some.js

@@ -56,7 +56,7 @@ 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' || thisArg !== undefined) {
     predicate = baseCallback(predicate, thisArg, 3);

collection/sortBy.js

@@ -57,7 +57,7 @@ function sortBy(collection, iteratee, thisArg) {
     return [];
   }
   if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
-    iteratee = null;
+    iteratee = undefined;
   }
   var index = -1;
   iteratee = baseCallback(iteratee, thisArg, 3);

collection/sortByOrder.js

@@ -4,9 +4,9 @@ import isIterateeCall from '../internal/isIterateeCall';
 
 /**
  * This method is like `_.sortByAll` except that it allows specifying the
- * sort orders of the iteratees to sort by. A truthy value in `orders` will
- * sort the corresponding property name in ascending order while a falsey
- * value will sort it in descending order.
+ * 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.
@@ -20,7 +20,7 @@ import isIterateeCall from '../internal/isIterateeCall';
  * @category Collection
  * @param {Array|Object|string} collection The collection to iterate over.
  * @param {Function[]|Object[]|string[]} iteratees The iteratees to sort by.
- * @param {boolean[]} orders The sort orders of `iteratees`.
+ * @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
@@ -33,7 +33,7 @@ import isIterateeCall from '../internal/isIterateeCall';
  * ];
  *
  * // sort by `user` in ascending order and by `age` in descending order
- * _.map(_.sortByOrder(users, ['user', 'age'], [true, false]), _.values);
+ * _.map(_.sortByOrder(users, ['user', 'age'], ['asc', 'desc']), _.values);
  * // => [['barney', 36], ['barney', 34], ['fred', 48], ['fred', 42]]
  */
 function sortByOrder(collection, iteratees, orders, guard) {
@@ -41,7 +41,7 @@ function sortByOrder(collection, iteratees, orders, guard) {
     return [];
   }
   if (guard && isIterateeCall(iteratees, orders, guard)) {
-    orders = null;
+    orders = undefined;
   }
   if (!isArray(iteratees)) {
     iteratees = iteratees == null ? [] : [iteratees];

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

@@ -33,7 +33,7 @@ function before(n, func) {
       result = func.apply(this, arguments);
     }
     if (n <= 1) {
-      func = null;
+      func = undefined;
     }
     return result;
   };

function/debounce.js

@@ -90,9 +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() {
@@ -102,41 +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() {
@@ -176,7 +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

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/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/throttle.js

@@ -4,13 +4,6 @@ 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 throttled function that only invokes `func` at most once per
  * every `wait` milliseconds. The throttled function comes with a `cancel`
@@ -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/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/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/baseClone.js

@@ -53,7 +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;
@@ -104,7 +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/baseCreate.js

@@ -14,7 +14,7 @@ var baseCreate = (function() {
     if (isObject(prototype)) {
       object.prototype = prototype;
       var result = new object;
-      object.prototype = null;
+      object.prototype = undefined;
     }
     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/baseFlatten.js

@@ -1,3 +1,4 @@
+import arrayPush from './arrayPush';
 import isArguments from '../lang/isArguments';
 import isArray from '../lang/isArray';
 import isArrayLike from './isArrayLike';
@@ -11,13 +12,14 @@ import isObjectLike from './isObjectLike';
  * @param {Array} array The array to flatten.
  * @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];
@@ -25,16 +27,12 @@ function baseFlatten(array, isDeep, isStrict) {
         (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;
-
-      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/baseIsEqualDeep.js

@@ -16,7 +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;

internal/baseMerge.js

@@ -14,7 +14,7 @@ import keys from '../object/keys';
  * @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 `object`.
@@ -24,7 +24,7 @@ function baseMerge(object, source, customizer, stackA, stackB) {
     return object;
   }
   var isSrcArr = isArrayLike(source) && (isArray(source) || isTypedArray(source)),
-      props = isSrcArr ? null : keys(source);
+      props = isSrcArr ? undefined : keys(source);
 
   arrayEach(props || source, function(srcValue, key) {
     if (props) {

internal/baseMergeDeep.js

@@ -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`.

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/baseToString.js

@@ -7,9 +7,6 @@
  * @returns {string} Returns the string.
  */
 function baseToString(value) {
-  if (typeof value == 'string') {
-    return value;
-  }
   return value == null ? '' : (value + '');
 }
 

internal/baseUniq.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 `_.uniq` without support for callback shorthands
  * and `this` binding.
@@ -16,7 +19,7 @@ function baseUniq(array, iteratee) {
       indexOf = baseIndexOf,
       length = array.length,
       isCommon = true,
-      isLarge = isCommon && length >= 200,
+      isLarge = isCommon && length >= LARGE_ARRAY_SIZE,
       seen = isLarge ? createCache() : null,
       result = [];
 

internal/baseWrapperValue.js

@@ -1,10 +1,5 @@
 import LazyWrapper from './LazyWrapper';
-
-/** Used for native method references. */
-var arrayProto = Array.prototype;
-
-/** Native method references. */
-var push = arrayProto.push;
+import arrayPush from './arrayPush';
 
 /**
  * The base implementation of `wrapperValue` which returns the result of
@@ -25,11 +20,8 @@ function baseWrapperValue(value, actions) {
       length = actions.length;
 
   while (++index < length) {
-    var args = [result],
-        action = actions[index];
-
-    push.apply(args, action.args);
-    result = action.func.apply(action.thisArg, args);
+    var action = actions[index];
+    result = action.func.apply(action.thisArg, arrayPush([result], action.args));
   }
   return result;
 }

internal/binaryIndexBy.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 nativeMin = Math.min;
+var nativeFloor = Math.floor,
+    nativeMin = Math.min;
 
 /** Used as references for the maximum length and index of an array. */
 var MAX_ARRAY_LENGTH = 4294967295,
@@ -31,7 +29,7 @@ function binaryIndexBy(array, value, iteratee, retHighest) {
       valIsUndef = value === undefined;
 
   while (low < high) {
-    var mid = floor((low + high) / 2),
+    var mid = nativeFloor((low + high) / 2),
         computed = iteratee(array[mid]),
         isDef = computed !== undefined,
         isReflexive = computed === computed;

internal/bufferClone.js

@@ -1,27 +1,8 @@
-import constant from '../utility/constant';
-import getNative from './getNative';
 import root from './root';
 
 /** Native method references. */
-var ArrayBuffer = getNative(root, 'ArrayBuffer'),
-    bufferSlice = getNative(ArrayBuffer && new ArrayBuffer(0), 'slice'),
-    floor = Math.floor,
-    Uint8Array = getNative(root, 'Uint8Array');
-
-/** Used to clone array buffers. */
-var Float64Array = (function() {
-  // Safari 5 errors when using an array buffer to initialize a typed array
-  // where the array buffer's `byteLength` is not a multiple of the typed
-  // array's `BYTES_PER_ELEMENT`.
-  try {
-    var func = getNative(root, 'Float64Array'),
-        result = new func(new ArrayBuffer(10), 0, 1) && func;
-  } catch(e) {}
-  return result || null;
-}());
-
-/** Used as the size, in bytes, of each `Float64Array` element. */
-var FLOAT64_BYTES_PER_ELEMENT = Float64Array ? Float64Array.BYTES_PER_ELEMENT : 0;
+var ArrayBuffer = root.ArrayBuffer,
+    Uint8Array = root.Uint8Array;
 
 /**
  * Creates a clone of the given array buffer.
@@ -31,26 +12,11 @@ var FLOAT64_BYTES_PER_ELEMENT = Float64Array ? Float64Array.BYTES_PER_ELEMENT :
  * @returns {ArrayBuffer} Returns the cloned array buffer.
  */
 function bufferClone(buffer) {
-  return bufferSlice.call(buffer, 0);
-}
-if (!bufferSlice) {
-  // PhantomJS has `ArrayBuffer` and `Uint8Array` but not `Float64Array`.
-  bufferClone = !(ArrayBuffer && Uint8Array) ? constant(null) : function(buffer) {
-    var byteLength = buffer.byteLength,
-        floatLength = Float64Array ? floor(byteLength / FLOAT64_BYTES_PER_ELEMENT) : 0,
-        offset = floatLength * FLOAT64_BYTES_PER_ELEMENT,
-        result = new ArrayBuffer(byteLength);
+  var result = new ArrayBuffer(buffer.byteLength),
+      view = new Uint8Array(result);
 
-    if (floatLength) {
-      var view = new Float64Array(result, 0, floatLength);
-      view.set(new Float64Array(buffer, 0, floatLength));
-    }
-    if (byteLength != offset) {
-      view = new Uint8Array(result, offset);
-      view.set(new Uint8Array(buffer, offset));
-    }
-    return result;
-  };
+  view.set(new Uint8Array(buffer));
+  return result;
 }
 
 export default bufferClone;

internal/compareAscending.js

@@ -5,8 +5,8 @@ import baseCompareAscending from './baseCompareAscending';
  * sort them in ascending order.
  *
  * @private
- * @param {Object} object The object to compare to `other`.
- * @param {Object} other The object to compare to `object`.
+ * @param {Object} object The object to compare.
+ * @param {Object} other The other object to compare.
  * @returns {number} Returns the sort order indicator for `object`.
  */
 function compareAscending(object, other) {

internal/compareMultiple.js

@@ -1,16 +1,16 @@
 import baseCompareAscending from './baseCompareAscending';
 
 /**
- * Used by `_.sortByOrder` to compare multiple properties of each element
- * in a collection and stable sort them in the following order:
+ * Used by `_.sortByOrder` to compare multiple properties of a value to another
+ * and stable sort them.
  *
- * If `orders` is unspecified, sort in ascending order for all properties.
- * Otherwise, for each property, sort in ascending order if its corresponding value in
- * orders is true, and descending order if false.
+ * If `orders` is unspecified, all valuess are sorted in ascending order. Otherwise,
+ * a value is sorted in ascending order if its corresponding order is "asc", and
+ * descending if "desc".
  *
  * @private
- * @param {Object} object The object to compare to `other`.
- * @param {Object} other The object to compare to `object`.
+ * @param {Object} object The object to compare.
+ * @param {Object} other The other object to compare.
  * @param {boolean[]} orders The order to sort by for each property.
  * @returns {number} Returns the sort order indicator for `object`.
  */
@@ -27,7 +27,8 @@ function compareMultiple(object, other, orders) {
       if (index >= ordersLength) {
         return result;
       }
-      return result * (orders[index] ? 1 : -1);
+      var order = orders[index];
+      return result * ((order === 'asc' || order === true) ? 1 : -1);
     }
   }
   // Fixes an `Array#sort` bug in the JS engine embedded in Adobe applications

internal/composeArgs.js

@@ -17,7 +17,7 @@ function composeArgs(args, partials, holders) {
       argsLength = nativeMax(args.length - holdersLength, 0),
       leftIndex = -1,
       leftLength = partials.length,
-      result = Array(argsLength + leftLength);
+      result = Array(leftLength + argsLength);
 
   while (++leftIndex < leftLength) {
     result[leftIndex] = partials[leftIndex];

internal/createAggregator.js

@@ -3,12 +3,7 @@ import baseEach from './baseEach';
 import isArray from '../lang/isArray';
 
 /**
- * Creates a function that aggregates a collection, creating an accumulator
- * object composed from the results of running each element in the collection
- * through an iteratee.
- *
- * **Note:** This function is used to create `_.countBy`, `_.groupBy`, `_.indexBy`,
- * and `_.partition`.
+ * Creates a `_.countBy`, `_.groupBy`, `_.indexBy`, or `_.partition` function.
  *
  * @private
  * @param {Function} setter The function to set keys and values of the accumulator object.

internal/createAssigner.js

@@ -3,10 +3,7 @@ import isIterateeCall from './isIterateeCall';
 import restParam from '../function/restParam';
 
 /**
- * Creates a function that assigns properties of source object(s) to a given
- * destination object.
- *
- * **Note:** This function is used to create `_.assign`, `_.defaults`, and `_.merge`.
+ * Creates a `_.assign`, `_.defaults`, or `_.merge` function.
  *
  * @private
  * @param {Function} assigner The function to assign values.

internal/createCache.js

@@ -1,5 +1,4 @@
 import SetCache from './SetCache';
-import constant from '../utility/constant';
 import getNative from './getNative';
 import root from './root';
 
@@ -16,8 +15,8 @@ var nativeCreate = getNative(Object, 'create');
  * @param {Array} [values] The values to cache.
  * @returns {null|Object} Returns the new cache object if `Set` is supported, else `null`.
  */
-var createCache = !(nativeCreate && Set) ? constant(null) : function(values) {
-  return new SetCache(values);
-};
+function createCache(values) {
+  return (nativeCreate && Set) ? new SetCache(values) : null;
+}
 
 export default createCache;

internal/createCtorWrapper.js

@@ -12,7 +12,7 @@ import isObject from '../lang/isObject';
 function createCtorWrapper(Ctor) {
   return function() {
     // Use a `switch` statement to work with class constructors.
-    // See https://people.mozilla.org/~jorendorff/es6-draft.html#sec-ecmascript-function-objects-call-thisargument-argumentslist
+    // See http://ecma-international.org/ecma-262/6.0/#sec-ecmascript-function-objects-call-thisargument-argumentslist
     // for more details.
     var args = arguments;
     switch (args.length) {
@@ -22,6 +22,8 @@ function createCtorWrapper(Ctor) {
       case 3: return new Ctor(args[0], args[1], args[2]);
       case 4: return new Ctor(args[0], args[1], args[2], args[3]);
       case 5: return new Ctor(args[0], args[1], args[2], args[3], args[4]);
+      case 6: return new Ctor(args[0], args[1], args[2], args[3], args[4], args[5]);
+      case 7: return new Ctor(args[0], args[1], args[2], args[3], args[4], args[5], args[6]);
     }
     var thisBinding = baseCreate(Ctor.prototype),
         result = Ctor.apply(thisBinding, args);

internal/createCurry.js

@@ -11,9 +11,9 @@ import isIterateeCall from './isIterateeCall';
 function createCurry(flag) {
   function curryFunc(func, arity, guard) {
     if (guard && isIterateeCall(func, arity, guard)) {
-      arity = null;
+      arity = undefined;
     }
-    var result = createWrapper(func, flag, null, null, null, null, null, arity);
+    var result = createWrapper(func, flag, undefined, undefined, undefined, undefined, undefined, arity);
     result.placeholder = curryFunc.placeholder;
     return result;
   }

internal/createDefaults.js

@@ -0,0 +1,22 @@
+import restParam from '../function/restParam';
+
+/**
+ * Creates a `_.defaults` or `_.defaultsDeep` function.
+ *
+ * @private
+ * @param {Function} assigner The function to assign values.
+ * @param {Function} customizer The function to customize assigned values.
+ * @returns {Function} Returns the new defaults function.
+ */
+function createDefaults(assigner, customizer) {
+  return restParam(function(args) {
+    var object = args[0];
+    if (object == null) {
+      return object;
+    }
+    args.push(customizer);
+    return assigner.apply(undefined, args);
+  });
+}
+
+export default createDefaults;

internal/createExtremum.js

@@ -1,6 +1,7 @@
 import arrayExtremum from './arrayExtremum';
 import baseCallback from './baseCallback';
 import baseExtremum from './baseExtremum';
+import isArray from '../lang/isArray';
 import isIterateeCall from './isIterateeCall';
 import toIterable from './toIterable';
 
@@ -15,11 +16,11 @@ import toIterable from './toIterable';
 function createExtremum(comparator, exValue) {
   return function(collection, iteratee, thisArg) {
     if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
-      iteratee = null;
+      iteratee = undefined;
     }
     iteratee = baseCallback(iteratee, thisArg, 3);
     if (iteratee.length == 1) {
-      collection = toIterable(collection);
+      collection = isArray(collection) ? collection : toIterable(collection);
       var result = arrayExtremum(collection, iteratee, comparator, exValue);
       if (!(collection.length && result === exValue)) {
         return result;

internal/createFlow.js

@@ -10,6 +10,9 @@ var CURRY_FLAG = 8,
     ARY_FLAG = 128,
     REARG_FLAG = 256;
 
+/** Used as the size to enable large array optimizations. */
+var LARGE_ARRAY_SIZE = 200;
+
 /** Used as the `TypeError` message for "Functions" methods. */
 var FUNC_ERROR_TEXT = 'Expected a function';
 
@@ -34,7 +37,7 @@ function createFlow(fromRight) {
         throw new TypeError(FUNC_ERROR_TEXT);
       }
       if (!wrapper && LodashWrapper.prototype.thru && getFuncName(func) == 'wrapper') {
-        wrapper = new LodashWrapper([]);
+        wrapper = new LodashWrapper([], true);
       }
     }
     index = wrapper ? -1 : length;
@@ -42,7 +45,7 @@ function createFlow(fromRight) {
       func = funcs[index];
 
       var funcName = getFuncName(func),
-          data = funcName == 'wrapper' ? getData(func) : null;
+          data = funcName == 'wrapper' ? getData(func) : undefined;
 
       if (data && isLaziable(data[0]) && data[1] == (ARY_FLAG | CURRY_FLAG | PARTIAL_FLAG | REARG_FLAG) && !data[4].length && data[9] == 1) {
         wrapper = wrapper[getFuncName(data[0])].apply(wrapper, data[3]);
@@ -51,12 +54,14 @@ function createFlow(fromRight) {
       }
     }
     return function() {
-      var args = arguments;
-      if (wrapper && args.length == 1 && isArray(args[0])) {
-        return wrapper.plant(args[0]).value();
+      var args = arguments,
+          value = args[0];
+
+      if (wrapper && args.length == 1 && isArray(value) && value.length >= LARGE_ARRAY_SIZE) {
+        return wrapper.plant(value).value();
       }
       var index = 0,
-          result = length ? funcs[index].apply(this, args) : args[0];
+          result = length ? funcs[index].apply(this, args) : value;
 
       while (++index < length) {
         result = funcs[index].call(this, result);

internal/createHybridWrapper.js

@@ -45,7 +45,7 @@ function createHybridWrapper(func, bitmask, thisArg, partials, holders, partials
       isCurry = bitmask & CURRY_FLAG,
       isCurryBound = bitmask & CURRY_BOUND_FLAG,
       isCurryRight = bitmask & CURRY_RIGHT_FLAG,
-      Ctor = isBindKey ? null : createCtorWrapper(func);
+      Ctor = isBindKey ? undefined : createCtorWrapper(func);
 
   function wrapper() {
     // Avoid `arguments` object use disqualifying optimizations by
@@ -69,12 +69,12 @@ function createHybridWrapper(func, bitmask, thisArg, partials, holders, partials
 
       length -= argsHolders.length;
       if (length < arity) {
-        var newArgPos = argPos ? arrayCopy(argPos) : null,
+        var newArgPos = argPos ? arrayCopy(argPos) : undefined,
             newArity = nativeMax(arity - length, 0),
-            newsHolders = isCurry ? argsHolders : null,
-            newHoldersRight = isCurry ? null : argsHolders,
-            newPartials = isCurry ? args : null,
-            newPartialsRight = isCurry ? null : args;
+            newsHolders = isCurry ? argsHolders : undefined,
+            newHoldersRight = isCurry ? undefined : argsHolders,
+            newPartials = isCurry ? args : undefined,
+            newPartialsRight = isCurry ? undefined : args;
 
         bitmask |= (isCurry ? PARTIAL_FLAG : PARTIAL_RIGHT_FLAG);
         bitmask &= ~(isCurry ? PARTIAL_RIGHT_FLAG : PARTIAL_FLAG);

internal/createPadding.js

@@ -1,11 +1,9 @@
 import repeat from '../string/repeat';
 import root from './root';
 
-/** Native method references. */
-var ceil = Math.ceil;
-
 /* Native method references for those with the same name as other `lodash` methods. */
-var nativeIsFinite = root.isFinite;
+var nativeCeil = Math.ceil,
+    nativeIsFinite = root.isFinite;
 
 /**
  * Creates the padding required for `string` based on the given `length`.
@@ -26,7 +24,7 @@ function createPadding(string, length, chars) {
   }
   var padLength = length - strLength;
   chars = chars == null ? ' ' : (chars + '');
-  return repeat(chars, ceil(padLength / chars.length)).slice(0, padLength);
+  return repeat(chars, nativeCeil(padLength / chars.length)).slice(0, padLength);
 }
 
 export default createPadding;

internal/createPartial.js

@@ -12,7 +12,7 @@ import restParam from '../function/restParam';
 function createPartial(flag) {
   var partialFunc = restParam(function(func, partials) {
     var holders = replaceHolders(partials, partialFunc.placeholder);
-    return createWrapper(func, flag, null, partials, holders);
+    return createWrapper(func, flag, undefined, partials, holders);
   });
   return partialFunc;
 }

internal/createPartialWrapper.js

@@ -27,7 +27,7 @@ function createPartialWrapper(func, bitmask, thisArg, partials) {
         argsLength = arguments.length,
         leftIndex = -1,
         leftLength = partials.length,
-        args = Array(argsLength + leftLength);
+        args = Array(leftLength + argsLength);
 
     while (++leftIndex < leftLength) {
       args[leftIndex] = partials[leftIndex];

internal/createRound.js

@@ -0,0 +1,23 @@
+/** Native method references. */
+var pow = Math.pow;
+
+/**
+ * Creates a `_.ceil`, `_.floor`, or `_.round` function.
+ *
+ * @private
+ * @param {string} methodName The name of the `Math` method to use when rounding.
+ * @returns {Function} Returns the new round function.
+ */
+function createRound(methodName) {
+  var func = Math[methodName];
+  return function(number, precision) {
+    precision = precision === undefined ? 0 : (+precision || 0);
+    if (precision) {
+      precision = pow(10, precision);
+      return func(number * precision) / precision;
+    }
+    return func(number);
+  };
+}
+
+export default createRound;

internal/createWrapper.js

@@ -51,16 +51,16 @@ function createWrapper(func, bitmask, thisArg, partials, holders, argPos, ary, a
   var length = partials ? partials.length : 0;
   if (!length) {
     bitmask &= ~(PARTIAL_FLAG | PARTIAL_RIGHT_FLAG);
-    partials = holders = null;
+    partials = holders = undefined;
   }
   length -= (holders ? holders.length : 0);
   if (bitmask & PARTIAL_RIGHT_FLAG) {
     var partialsRight = partials,
         holdersRight = holders;
 
-    partials = holders = null;
+    partials = holders = undefined;
   }
-  var data = isBindKey ? null : getData(func),
+  var data = isBindKey ? undefined : getData(func),
       newData = [func, bitmask, thisArg, partials, holders, partialsRight, holdersRight, argPos, ary, arity];
 
   if (data) {

internal/equalByTag.js

@@ -14,7 +14,7 @@ var boolTag = '[object Boolean]',
  * `Boolean`, `Date`, `Error`, `Number`, `RegExp`, or `String`.
  *
  * @private
- * @param {Object} value The object to compare.
+ * @param {Object} object The object to compare.
  * @param {Object} other The other object to compare.
  * @param {string} tag The `toStringTag` of the objects to compare.
  * @returns {boolean} Returns `true` if the objects are equivalent, else `false`.

internal/escapeRegExpChar.js

@@ -0,0 +1,38 @@
+/** Used to escape characters for inclusion in compiled regexes. */
+var regexpEscapes = {
+  '0': 'x30', '1': 'x31', '2': 'x32', '3': 'x33', '4': 'x34',
+  '5': 'x35', '6': 'x36', '7': 'x37', '8': 'x38', '9': 'x39',
+  'A': 'x41', 'B': 'x42', 'C': 'x43', 'D': 'x44', 'E': 'x45', 'F': 'x46',
+  'a': 'x61', 'b': 'x62', 'c': 'x63', 'd': 'x64', 'e': 'x65', 'f': 'x66',
+  'n': 'x6e', 'r': 'x72', 't': 'x74', 'u': 'x75', 'v': 'x76', 'x': 'x78'
+};
+
+/** Used to escape characters for inclusion in compiled string literals. */
+var stringEscapes = {
+  '\\': '\\',
+  "'": "'",
+  '\n': 'n',
+  '\r': 'r',
+  '\u2028': 'u2028',
+  '\u2029': 'u2029'
+};
+
+/**
+ * Used by `_.escapeRegExp` to escape characters for inclusion in compiled regexes.
+ *
+ * @private
+ * @param {string} chr The matched character to escape.
+ * @param {string} leadingChar The capture group for a leading character.
+ * @param {string} whitespaceChar The capture group for a whitespace character.
+ * @returns {string} Returns the escaped character.
+ */
+function escapeRegExpChar(chr, leadingChar, whitespaceChar) {
+  if (leadingChar) {
+    chr = regexpEscapes[chr];
+  } else if (whitespaceChar) {
+    chr = stringEscapes[chr];
+  }
+  return '\\' + chr;
+}
+
+export default escapeRegExpChar;

internal/escapeStringChar.js

@@ -9,8 +9,7 @@ var stringEscapes = {
 };
 
 /**
- * Used by `_.template` to escape characters for inclusion in compiled
- * string literals.
+ * Used by `_.template` to escape characters for inclusion in compiled string literals.
  *
  * @private
  * @param {string} chr The matched character to escape.

internal/getView.js

@@ -8,13 +8,13 @@ var nativeMax = Math.max,
  * @private
  * @param {number} start The start of the view.
  * @param {number} end The end of the view.
- * @param {Array} [transforms] The transformations to apply to the view.
+ * @param {Array} transforms The transformations to apply to the view.
  * @returns {Object} Returns an object containing the `start` and `end`
  *  positions of the view.
  */
 function getView(start, end, transforms) {
   var index = -1,
-      length = transforms ? transforms.length : 0;
+      length = transforms.length;
 
   while (++index < length) {
     var data = transforms[index],

internal/isIndex.js

@@ -2,7 +2,7 @@
 var reIsUint = /^\d+$/;
 
 /**
- * Used as the [maximum length](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-number.max_safe_integer)
+ * Used as the [maximum length](http://ecma-international.org/ecma-262/6.0/#sec-number.max_safe_integer)
  * of an array-like value.
  */
 var MAX_SAFE_INTEGER = 9007199254740991;

internal/isLength.js

@@ -1,5 +1,5 @@
 /**
- * Used as the [maximum length](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-number.max_safe_integer)
+ * Used as the [maximum length](http://ecma-international.org/ecma-262/6.0/#sec-number.max_safe_integer)
  * of an array-like value.
  */
 var MAX_SAFE_INTEGER = 9007199254740991;
@@ -7,7 +7,7 @@ var MAX_SAFE_INTEGER = 9007199254740991;
 /**
  * Checks if `value` is a valid array-like length.
  *
- * **Note:** This function is based on [`ToLength`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-tolength).
+ * **Note:** This function is based on [`ToLength`](http://ecma-international.org/ecma-262/6.0/#sec-tolength).
  *
  * @private
  * @param {*} value The value to check.

internal/lazyClone.js

@@ -10,17 +10,13 @@ import arrayCopy from './arrayCopy';
  * @returns {Object} Returns the cloned `LazyWrapper` object.
  */
 function lazyClone() {
-  var actions = this.__actions__,
-      iteratees = this.__iteratees__,
-      views = this.__views__,
-      result = new LazyWrapper(this.__wrapped__);
-
-  result.__actions__ = actions ? arrayCopy(actions) : null;
+  var result = new LazyWrapper(this.__wrapped__);
+  result.__actions__ = arrayCopy(this.__actions__);
   result.__dir__ = this.__dir__;
   result.__filtered__ = this.__filtered__;
-  result.__iteratees__ = iteratees ? arrayCopy(iteratees) : null;
+  result.__iteratees__ = arrayCopy(this.__iteratees__);
   result.__takeCount__ = this.__takeCount__;
-  result.__views__ = views ? arrayCopy(views) : null;
+  result.__views__ = arrayCopy(this.__views__);
   return result;
 }
 

internal/lazyValue.js

@@ -2,9 +2,11 @@ import baseWrapperValue from './baseWrapperValue';
 import getView from './getView';
 import isArray from '../lang/isArray';
 
+/** Used as the size to enable large array optimizations. */
+var LARGE_ARRAY_SIZE = 200;
+
 /** Used to indicate the type of lazy iteratees. */
-var LAZY_DROP_WHILE_FLAG = 0,
-    LAZY_FILTER_FLAG = 1,
+var LAZY_FILTER_FLAG = 1,
     LAZY_MAP_FLAG = 2;
 
 /* Native method references for those with the same name as other `lodash` methods. */
@@ -19,22 +21,25 @@ var nativeMin = Math.min;
  * @returns {*} Returns the unwrapped value.
  */
 function lazyValue() {
-  var array = this.__wrapped__.value();
-  if (!isArray(array)) {
-    return baseWrapperValue(array, this.__actions__);
-  }
-  var dir = this.__dir__,
+  var array = this.__wrapped__.value(),
+      dir = this.__dir__,
+      isArr = isArray(array),
       isRight = dir < 0,
-      view = getView(0, array.length, this.__views__),
+      arrLength = isArr ? array.length : 0,
+      view = getView(0, arrLength, this.__views__),
       start = view.start,
       end = view.end,
       length = end - start,
       index = isRight ? end : (start - 1),
-      takeCount = nativeMin(length, this.__takeCount__),
       iteratees = this.__iteratees__,
-      iterLength = iteratees ? iteratees.length : 0,
+      iterLength = iteratees.length,
       resIndex = 0,
-      result = [];
+      takeCount = nativeMin(length, this.__takeCount__);
+
+  if (!isArr || arrLength < LARGE_ARRAY_SIZE || (arrLength == length && takeCount == length)) {
+    return baseWrapperValue((isRight && isArr) ? array.reverse() : array, this.__actions__);
+  }
+  var result = [];
 
   outer:
   while (length-- && resIndex < takeCount) {
@@ -46,30 +51,16 @@ function lazyValue() {
     while (++iterIndex < iterLength) {
       var data = iteratees[iterIndex],
           iteratee = data.iteratee,
-          type = data.type;
+          type = data.type,
+          computed = iteratee(value);
 
-      if (type == LAZY_DROP_WHILE_FLAG) {
-        if (data.done && (isRight ? (index > data.index) : (index < data.index))) {
-          data.count = 0;
-          data.done = false;
-        }
-        data.index = index;
-        if (!data.done) {
-          var limit = data.limit;
-          if (!(data.done = limit > -1 ? (data.count++ >= limit) : !iteratee(value))) {
-            continue outer;
-          }
-        }
-      } else {
-        var computed = iteratee(value);
-        if (type == LAZY_MAP_FLAG) {
-          value = computed;
-        } else if (!computed) {
-          if (type == LAZY_FILTER_FLAG) {
-            continue outer;
-          } else {
-            break outer;
-          }
+      if (type == LAZY_MAP_FLAG) {
+        value = computed;
+      } else if (!computed) {
+        if (type == LAZY_FILTER_FLAG) {
+          continue outer;
+        } else {
+          break outer;
         }
       }
     }

internal/mergeDefaults.js

@@ -0,0 +1,15 @@
+import merge from '../object/merge';
+
+/**
+ * Used by `_.defaultsDeep` to customize its `_.merge` use.
+ *
+ * @private
+ * @param {*} objectValue The destination object property value.
+ * @param {*} sourceValue The source object property value.
+ * @returns {*} Returns the value to assign to the destination object.
+ */
+function mergeDefaults(objectValue, sourceValue) {
+  return objectValue === undefined ? sourceValue : merge(objectValue, sourceValue, mergeDefaults);
+}
+
+export default mergeDefaults;

internal/shimIsPlainObject.js

@@ -1,50 +0,0 @@
-import baseForIn from './baseForIn';
-import isObjectLike from './isObjectLike';
-
-/** `Object#toString` result references. */
-var objectTag = '[object Object]';
-
-/** Used for native method references. */
-var objectProto = Object.prototype;
-
-/** Used to check objects for own properties. */
-var hasOwnProperty = objectProto.hasOwnProperty;
-
-/**
- * Used to resolve the [`toStringTag`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.prototype.tostring)
- * of values.
- */
-var objToString = objectProto.toString;
-
-/**
- * A fallback implementation of `_.isPlainObject` which checks if `value`
- * is an object created by the `Object` constructor or has a `[[Prototype]]`
- * of `null`.
- *
- * @private
- * @param {*} value The value to check.
- * @returns {boolean} Returns `true` if `value` is a plain object, else `false`.
- */
-function shimIsPlainObject(value) {
-  var Ctor;
-
-  // Exit early for non `Object` objects.
-  if (!(isObjectLike(value) && objToString.call(value) == objectTag) ||
-      (!hasOwnProperty.call(value, 'constructor') &&
-        (Ctor = value.constructor, typeof Ctor == 'function' && !(Ctor instanceof Ctor)))) {
-    return false;
-  }
-  // IE < 9 iterates inherited properties before own properties. If the first
-  // iterated property is an object's own property then there are no inherited
-  // enumerable properties.
-  var result;
-  // In most environments an object's own properties are iterated before
-  // its inherited properties. If the last iterated property is an object's
-  // own property then there are no inherited enumerable properties.
-  baseForIn(value, function(subValue, key) {
-    result = key;
-  });
-  return result === undefined || hasOwnProperty.call(value, result);
-}
-
-export default shimIsPlainObject;

lang/isArguments.js

@@ -1,17 +1,14 @@
 import isArrayLike from '../internal/isArrayLike';
 import isObjectLike from '../internal/isObjectLike';
 
-/** `Object#toString` result references. */
-var argsTag = '[object Arguments]';
-
 /** Used for native method references. */
 var objectProto = Object.prototype;
 
-/**
- * Used to resolve the [`toStringTag`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.prototype.tostring)
- * of values.
- */
-var objToString = objectProto.toString;
+/** Used to check objects for own properties. */
+var hasOwnProperty = objectProto.hasOwnProperty;
+
+/** Native method references. */
+var propertyIsEnumerable = objectProto.propertyIsEnumerable;
 
 /**
  * Checks if `value` is classified as an `arguments` object.
@@ -30,7 +27,8 @@ var objToString = objectProto.toString;
  * // => false
  */
 function isArguments(value) {
-  return isObjectLike(value) && isArrayLike(value) && objToString.call(value) == argsTag;
+  return isObjectLike(value) && isArrayLike(value) &&
+    hasOwnProperty.call(value, 'callee') && !propertyIsEnumerable.call(value, 'callee');
 }
 
 export default isArguments;

lang/isArray.js

@@ -9,7 +9,7 @@ var arrayTag = '[object Array]';
 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;

lang/isBoolean.js

@@ -7,7 +7,7 @@ var boolTag = '[object Boolean]';
 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;

lang/isDate.js

@@ -7,7 +7,7 @@ var dateTag = '[object Date]';
 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;

lang/isElement.js

@@ -1,15 +1,5 @@
 import isObjectLike from '../internal/isObjectLike';
 import isPlainObject from './isPlainObject';
-import support from '../support';
-
-/** Used for native method references. */
-var objectProto = Object.prototype;
-
-/**
- * Used to resolve the [`toStringTag`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.prototype.tostring)
- * of values.
- */
-var objToString = objectProto.toString;
 
 /**
  * Checks if `value` is a DOM element.
@@ -28,14 +18,7 @@ var objToString = objectProto.toString;
  * // => false
  */
 function isElement(value) {
-  return !!value && value.nodeType === 1 && isObjectLike(value) &&
-    (objToString.call(value).indexOf('Element') > -1);
-}
-// Fallback for environments without DOM support.
-if (!support.dom) {
-  isElement = function(value) {
-    return !!value && value.nodeType === 1 && isObjectLike(value) && !isPlainObject(value);
-  };
+  return !!value && value.nodeType === 1 && isObjectLike(value) && !isPlainObject(value);
 }
 
 export default isElement;

lang/isError.js

@@ -7,7 +7,7 @@ var errorTag = '[object Error]';
 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;

lang/isFinite.js

@@ -1,14 +1,12 @@
-import getNative from '../internal/getNative';
 import root from '../internal/root';
 
 /* Native method references for those with the same name as other `lodash` methods. */
-var nativeIsFinite = root.isFinite,
-    nativeNumIsFinite = getNative(Number, 'isFinite');
+var nativeIsFinite = root.isFinite;
 
 /**
  * Checks if `value` is a finite primitive number.
  *
- * **Note:** This method is based on [`Number.isFinite`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-number.isfinite).
+ * **Note:** This method is based on [`Number.isFinite`](http://ecma-international.org/ecma-262/6.0/#sec-number.isfinite).
  *
  * @static
  * @memberOf _
@@ -32,8 +30,8 @@ var nativeIsFinite = root.isFinite,
  * _.isFinite(Infinity);
  * // => false
  */
-var isFinite = nativeNumIsFinite || function(value) {
+function isFinite(value) {
   return typeof value == 'number' && nativeIsFinite(value);
-};
+}
 
 export default isFinite;

lang/isFunction.js

@@ -1,6 +1,4 @@
-import baseIsFunction from '../internal/baseIsFunction';
-import getNative from '../internal/getNative';
-import root from '../internal/root';
+import isObject from './isObject';
 
 /** `Object#toString` result references. */
 var funcTag = '[object Function]';
@@ -9,14 +7,11 @@ var funcTag = '[object Function]';
 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;
 
-/** Native method references. */
-var Uint8Array = getNative(root, 'Uint8Array');
-
 /**
  * Checks if `value` is classified as a `Function` object.
  *
@@ -33,11 +28,11 @@ var Uint8Array = getNative(root, 'Uint8Array');
  * _.isFunction(/abc/);
  * // => false
  */
-var isFunction = !(baseIsFunction(/x/) || (Uint8Array && !baseIsFunction(Uint8Array))) ? baseIsFunction : function(value) {
+function isFunction(value) {
   // The use of `Object#toString` avoids issues with the `typeof` operator
   // in older versions of Chrome and Safari which return 'function' for regexes
   // and Safari 8 equivalents which return 'object' for typed array constructors.
-  return objToString.call(value) == funcTag;
-};
+  return isObject(value) && objToString.call(value) == funcTag;
+}
 
 export default isFunction;

lang/isNative.js

@@ -1,9 +1,6 @@
-import escapeRegExp from '../string/escapeRegExp';
+import isFunction from './isFunction';
 import isObjectLike from '../internal/isObjectLike';
 
-/** `Object#toString` result references. */
-var funcTag = '[object Function]';
-
 /** Used to detect host constructors (Safari > 5). */
 var reIsHostCtor = /^\[object .+?Constructor\]$/;
 
@@ -16,15 +13,9 @@ var fnToString = Function.prototype.toString;
 /** Used to check objects for own properties. */
 var hasOwnProperty = objectProto.hasOwnProperty;
 
-/**
- * Used to resolve the [`toStringTag`](https://people.mozilla.org/~jorendorff/es6-draft.html#sec-object.prototype.tostring)
- * of values.
- */
-var objToString = objectProto.toString;
-
 /** Used to detect if a method is native. */
 var reIsNative = RegExp('^' +
-  escapeRegExp(fnToString.call(hasOwnProperty))
+  fnToString.call(hasOwnProperty).replace(/[\\^$.*+?()[\]{}|]/g, '\\$&')
   .replace(/hasOwnProperty|(function).*?(?=\\\()| for .+?(?=\\\])/g, '$1.*?') + '$'
 );
 
@@ -48,7 +39,7 @@ function isNative(value) {
   if (value == null) {
     return false;
   }
-  if (objToString.call(value) == funcTag) {
+  if (isFunction(value)) {
     return reIsNative.test(fnToString.call(value));
   }
   return isObjectLike(value) && reIsHostCtor.test(value);

lang/isNumber.js

@@ -7,7 +7,7 @@ var numberTag = '[object Number]';
 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;

lang/isPlainObject.js

@@ -1,5 +1,6 @@
-import getNative from '../internal/getNative';
-import shimIsPlainObject from '../internal/shimIsPlainObject';
+import baseForIn from '../internal/baseForIn';
+import isArguments from './isArguments';
+import isObjectLike from '../internal/isObjectLike';
 
 /** `Object#toString` result references. */
 var objectTag = '[object Object]';
@@ -7,15 +8,15 @@ var objectTag = '[object Object]';
 /** Used for native method references. */
 var objectProto = Object.prototype;
 
+/** Used to check objects for own properties. */
+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;
 
-/** Native method references. */
-var getPrototypeOf = getNative(Object, 'getPrototypeOf');
-
 /**
  * Checks if `value` is a plain object, that is, an object created by the
  * `Object` constructor or one with a `[[Prototype]]` of `null`.
@@ -46,16 +47,25 @@ var getPrototypeOf = getNative(Object, 'getPrototypeOf');
  * _.isPlainObject(Object.create(null));
  * // => true
  */
-var isPlainObject = !getPrototypeOf ? shimIsPlainObject : function(value) {
-  if (!(value && objToString.call(value) == objectTag)) {
+function isPlainObject(value) {
+  var Ctor;
+
+  // Exit early for non `Object` objects.
+  if (!(isObjectLike(value) && objToString.call(value) == objectTag && !isArguments(value)) ||
+      (!hasOwnProperty.call(value, 'constructor') && (Ctor = value.constructor, typeof Ctor == 'function' && !(Ctor instanceof Ctor)))) {
     return false;
   }
-  var valueOf = getNative(value, 'valueOf'),
-      objProto = valueOf && (objProto = getPrototypeOf(valueOf)) && getPrototypeOf(objProto);
-
-  return objProto
-    ? (value == objProto || getPrototypeOf(value) == objProto)
-    : shimIsPlainObject(value);
-};
+  // IE < 9 iterates inherited properties before own properties. If the first
+  // iterated property is an object's own property then there are no inherited
+  // enumerable properties.
+  var result;
+  // In most environments an object's own properties are iterated before
+  // its inherited properties. If the last iterated property is an object's
+  // own property then there are no inherited enumerable properties.
+  baseForIn(value, function(subValue, key) {
+    result = key;
+  });
+  return result === undefined || hasOwnProperty.call(value, result);
+}
 
 export default isPlainObject;

lang/isRegExp.js

@@ -1,4 +1,4 @@
-import isObjectLike from '../internal/isObjectLike';
+import isObject from './isObject';
 
 /** `Object#toString` result references. */
 var regexpTag = '[object RegExp]';
@@ -7,7 +7,7 @@ var regexpTag = '[object RegExp]';
 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;
@@ -29,7 +29,7 @@ var objToString = objectProto.toString;
  * // => false
  */
 function isRegExp(value) {
-  return isObjectLike(value) && objToString.call(value) == regexpTag;
+  return isObject(value) && objToString.call(value) == regexpTag;
 }
 
 export default isRegExp;

lang/isString.js

@@ -7,7 +7,7 @@ var stringTag = '[object String]';
 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;

lang/isTypedArray.js

@@ -46,7 +46,7 @@ typedArrayTags[stringTag] = typedArrayTags[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;

lodash.js

@@ -1,6 +1,6 @@
 /**
  * @license
- * lodash 3.9.3 (Custom Build) <https://lodash.com/>
+ * lodash 3.10.0 (Custom Build) <https://lodash.com/>
  * Build: `lodash modularize modern exports="es" -o ./`
  * Copyright 2012-2015 The Dojo Foundation <http://dojofoundation.org/>
  * Based on Underscore.js 1.8.3 <http://underscorejs.org/LICENSE>
@@ -21,6 +21,7 @@ import utility from './utility';
 import LazyWrapper from './internal/LazyWrapper';
 import LodashWrapper from './internal/LodashWrapper';
 import arrayEach from './internal/arrayEach';
+import arrayPush from './internal/arrayPush';
 import baseCallback from './internal/baseCallback';
 import baseForOwn from './internal/baseForOwn';
 import baseFunctions from './internal/baseFunctions';
@@ -42,27 +43,26 @@ import support from './support';
 import thru from './chain/thru';
 
 /** Used as the semantic version number. */
-var VERSION = '3.9.3';
+var VERSION = '3.10.0';
 
 /** Used to compose bitmasks for wrapper metadata. */
 var BIND_KEY_FLAG = 2;
 
 /** Used to indicate the type of lazy iteratees. */
-var LAZY_DROP_WHILE_FLAG = 0,
-    LAZY_MAP_FLAG = 2;
+var LAZY_MAP_FLAG = 2;
 
 /** Used for native method references. */
 var arrayProto = Array.prototype,
     stringProto = String.prototype;
 
-/** Native method references. */
-var floor = Math.floor,
-    push = arrayProto.push;
-
 /* Native method references for those with the same name as other `lodash` methods. */
-var nativeMax = Math.max,
+var nativeFloor = Math.floor,
+    nativeMax = Math.max,
     nativeMin = Math.min;
 
+/** Used as references for `-Infinity` and `Infinity`. */
+var POSITIVE_INFINITY = Number.POSITIVE_INFINITY;
+
 // wrap `_.mixin` so it works when provided only one argument
 var mixin = (function(func) {
   return function(object, source, options) {
@@ -101,6 +101,7 @@ lodash.curry = func.curry;
 lodash.curryRight = func.curryRight;
 lodash.debounce = func.debounce;
 lodash.defaults = object.defaults;
+lodash.defaultsDeep = object.defaultsDeep;
 lodash.defer = func.defer;
 lodash.delay = func.delay;
 lodash.difference = array.difference;
@@ -139,6 +140,7 @@ lodash.merge = object.merge;
 lodash.method = utility.method;
 lodash.methodOf = utility.methodOf;
 lodash.mixin = mixin;
+lodash.modArgs = func.modArgs;
 lodash.negate = func.negate;
 lodash.omit = object.omit;
 lodash.once = func.once;
@@ -212,6 +214,7 @@ lodash.add = math.add;
 lodash.attempt = utility.attempt;
 lodash.camelCase = string.camelCase;
 lodash.capitalize = string.capitalize;
+lodash.ceil = math.ceil;
 lodash.clone = lang.clone;
 lodash.cloneDeep = lang.cloneDeep;
 lodash.deburr = string.deburr;
@@ -227,6 +230,7 @@ lodash.findLastIndex = array.findLastIndex;
 lodash.findLastKey = object.findLastKey;
 lodash.findWhere = collection.findWhere;
 lodash.first = array.first;
+lodash.floor = math.floor;
 lodash.get = object.get;
 lodash.gt = lang.gt;
 lodash.gte = lang.gte;
@@ -274,6 +278,7 @@ lodash.reduce = collection.reduce;
 lodash.reduceRight = collection.reduceRight;
 lodash.repeat = string.repeat;
 lodash.result = object.result;
+lodash.round = math.round;
 lodash.size = collection.size;
 lodash.snakeCase = string.snakeCase;
 lodash.some = collection.some;
@@ -342,48 +347,20 @@ arrayEach(['bind', 'bindKey', 'curry', 'curryRight', 'partial', 'partialRight'],
   lodash[methodName].placeholder = lodash;
 });
 
-// Add `LazyWrapper` methods that accept an `iteratee` value.
-arrayEach(['dropWhile', 'filter', 'map', 'takeWhile'], function(methodName, type) {
-  var isFilter = type != LAZY_MAP_FLAG,
-      isDropWhile = type == LAZY_DROP_WHILE_FLAG;
-
-  LazyWrapper.prototype[methodName] = function(iteratee, thisArg) {
-    var filtered = this.__filtered__,
-        result = (filtered && isDropWhile) ? new LazyWrapper(this) : this.clone(),
-        iteratees = result.__iteratees__ || (result.__iteratees__ = []);
-
-    iteratees.push({
-      'done': false,
-      'count': 0,
-      'index': 0,
-      'iteratee': baseCallback(iteratee, thisArg, 1),
-      'limit': -1,
-      'type': type
-    });
-
-    result.__filtered__ = filtered || isFilter;
-    return result;
-  };
-});
-
 // Add `LazyWrapper` methods for `_.drop` and `_.take` variants.
 arrayEach(['drop', 'take'], function(methodName, index) {
-  var whileName = methodName + 'While';
-
   LazyWrapper.prototype[methodName] = function(n) {
-    var filtered = this.__filtered__,
-        result = (filtered && !index) ? this.dropWhile() : this.clone();
+    var filtered = this.__filtered__;
+    if (filtered && !index) {
+      return new LazyWrapper(this);
+    }
+    n = n == null ? 1 : nativeMax(nativeFloor(n) || 0, 0);
 
-    n = n == null ? 1 : nativeMax(floor(n) || 0, 0);
+    var result = this.clone();
     if (filtered) {
-      if (index) {
-        result.__takeCount__ = nativeMin(result.__takeCount__, n);
-      } else {
-        last(result.__iteratees__).limit = n;
-      }
+      result.__takeCount__ = nativeMin(result.__takeCount__, n);
     } else {
-      var views = result.__views__ || (result.__views__ = []);
-      views.push({ 'size': n, 'type': methodName + (result.__dir__ < 0 ? 'Right' : '') });
+      result.__views__.push({ 'size': n, 'type': methodName + (result.__dir__ < 0 ? 'Right' : '') });
     }
     return result;
   };
@@ -391,9 +368,18 @@ arrayEach(['drop', 'take'], function(methodName, index) {
   LazyWrapper.prototype[methodName + 'Right'] = function(n) {
     return this.reverse()[methodName](n).reverse();
   };
+});
 
-  LazyWrapper.prototype[methodName + 'RightWhile'] = function(predicate, thisArg) {
-    return this.reverse()[whileName](predicate, thisArg).reverse();
+// Add `LazyWrapper` methods that accept an `iteratee` value.
+arrayEach(['filter', 'map', 'takeWhile'], function(methodName, index) {
+  var type = index + 1,
+      isFilter = type != LAZY_MAP_FLAG;
+
+  LazyWrapper.prototype[methodName] = function(iteratee, thisArg) {
+    var result = this.clone();
+    result.__iteratees__.push({ 'iteratee': baseCallback(iteratee, thisArg, 1), 'type': type });
+    result.__filtered__ = result.__filtered__ || isFilter;
+    return result;
   };
 });
 
@@ -411,7 +397,7 @@ arrayEach(['initial', 'rest'], function(methodName, index) {
   var dropName = 'drop' + (index ? '' : 'Right');
 
   LazyWrapper.prototype[methodName] = function() {
-    return this[dropName](1);
+    return this.__filtered__ ? new LazyWrapper(this) : this[dropName](1);
   };
 });
 
@@ -440,10 +426,13 @@ LazyWrapper.prototype.slice = function(start, end) {
   start = start == null ? 0 : (+start || 0);
 
   var result = this;
+  if (result.__filtered__ && (start > 0 || end < 0)) {
+    return new LazyWrapper(result);
+  }
   if (start < 0) {
-    result = this.takeRight(-start);
+    result = result.takeRight(-start);
   } else if (start) {
-    result = this.drop(start);
+    result = result.drop(start);
   }
   if (end !== undefined) {
     end = (+end || 0);
@@ -452,21 +441,25 @@ LazyWrapper.prototype.slice = function(start, end) {
   return result;
 };
 
+LazyWrapper.prototype.takeRightWhile = function(predicate, thisArg) {
+  return this.reverse().takeWhile(predicate, thisArg).reverse();
+};
+
 LazyWrapper.prototype.toArray = function() {
-  return this.drop(0);
+  return this.take(POSITIVE_INFINITY);
 };
 
 // Add `LazyWrapper` methods to `lodash.prototype`.
 baseForOwn(LazyWrapper.prototype, function(func, methodName) {
-  var lodashFunc = lodash[methodName];
+  var checkIteratee = /^(?:filter|map|reject)|While$/.test(methodName),
+      retUnwrapped = /^(?:first|last)$/.test(methodName),
+      lodashFunc = lodash[retUnwrapped ? ('take' + (methodName == 'last' ? 'Right' : '')) : methodName];
+
   if (!lodashFunc) {
     return;
   }
-  var checkIteratee = /^(?:filter|map|reject)|While$/.test(methodName),
-      retUnwrapped = /^(?:first|last)$/.test(methodName);
-
   lodash.prototype[methodName] = function() {
-    var args = arguments,
+    var args = retUnwrapped ? [1] : arguments,
         chainAll = this.__chain__,
         value = this.__wrapped__,
         isHybrid = !!this.__actions__.length,
@@ -475,28 +468,30 @@ baseForOwn(LazyWrapper.prototype, function(func, methodName) {
         useLazy = isLazy || isArray(value);
 
     if (useLazy && checkIteratee && typeof iteratee == 'function' && iteratee.length != 1) {
-      // avoid lazy use if the iteratee has a "length" value other than `1`
+      // Avoid lazy use if the iteratee has a "length" value other than `1`.
       isLazy = useLazy = false;
     }
-    var onlyLazy = isLazy && !isHybrid;
-    if (retUnwrapped && !chainAll) {
-      return onlyLazy
-        ? func.call(value)
-        : lodashFunc.call(lodash, this.value());
-    }
     var interceptor = function(value) {
-      var otherArgs = [value];
-      push.apply(otherArgs, args);
-      return lodashFunc.apply(lodash, otherArgs);
+      return (retUnwrapped && chainAll)
+        ? lodashFunc(value, 1)[0]
+        : lodashFunc.apply(undefined, arrayPush([value], args));
     };
-    if (useLazy) {
-      var wrapper = onlyLazy ? value : new LazyWrapper(this),
-          result = func.apply(wrapper, args);
 
-      if (!retUnwrapped && (isHybrid || result.__actions__)) {
-        var actions = result.__actions__ || (result.__actions__ = []);
-        actions.push({ 'func': thru, 'args': [interceptor], 'thisArg': lodash });
+    var action = { 'func': thru, 'args': [interceptor], 'thisArg': undefined },
+        onlyLazy = isLazy && !isHybrid;
+
+    if (retUnwrapped && !chainAll) {
+      if (onlyLazy) {
+        value = value.clone();
+        value.__actions__.push(action);
+        return func.call(value);
       }
+      return lodashFunc.call(undefined, this.value())[0];
+    }
+    if (!retUnwrapped && useLazy) {
+      value = onlyLazy ? value : new LazyWrapper(this);
+      var result = func.apply(value, args);
+      result.__actions__.push(action);
       return new LodashWrapper(result, chainAll);
     }
     return this.thru(interceptor);
@@ -504,7 +499,7 @@ baseForOwn(LazyWrapper.prototype, function(func, methodName) {
 });
 
 // Add `Array` and `String` methods to `lodash.prototype`.
-arrayEach(['concat', 'join', 'pop', 'push', 'replace', 'shift', 'sort', 'splice', 'split', 'unshift'], function(methodName) {
+arrayEach(['join', 'pop', 'push', 'replace', 'shift', 'sort', 'splice', 'split', 'unshift'], function(methodName) {
   var func = (/^(?:replace|split)$/.test(methodName) ? stringProto : arrayProto)[methodName],
       chainName = /^(?:push|sort|unshift)$/.test(methodName) ? 'tap' : 'thru',
       retUnwrapped = /^(?:join|pop|replace|shift)$/.test(methodName);
@@ -531,7 +526,7 @@ baseForOwn(LazyWrapper.prototype, function(func, methodName) {
   }
 });
 
-realNames[createHybridWrapper(null, BIND_KEY_FLAG).name] = [{ 'name': 'wrapper', 'func': null }];
+realNames[createHybridWrapper(undefined, BIND_KEY_FLAG).name] = [{ 'name': 'wrapper', 'func': undefined }];
 
 // Add functions to the lazy wrapper.
 LazyWrapper.prototype.clone = lazyClone;
@@ -541,6 +536,7 @@ LazyWrapper.prototype.value = lazyValue;
 // Add chaining functions to the `lodash` wrapper.
 lodash.prototype.chain = chain.wrapperChain;
 lodash.prototype.commit = chain.commit;
+lodash.prototype.concat = chain.concat;
 lodash.prototype.plant = chain.plant;
 lodash.prototype.reverse = chain.reverse;
 lodash.prototype.toString = chain.toString;

math.js

@@ -1,11 +1,17 @@
 import add from './math/add';
+import ceil from './math/ceil';
+import floor from './math/floor';
 import max from './math/max';
 import min from './math/min';
+import round from './math/round';
 import sum from './math/sum';
 
 export default {
   'add': add,
+  'ceil': ceil,
+  'floor': floor,
   'max': max,
   'min': min,
+  'round': round,
   'sum': sum
 };

math/ceil.js

@@ -0,0 +1,25 @@
+import createRound from '../internal/createRound';
+
+/**
+ * Calculates `n` rounded up to `precision`.
+ *
+ * @static
+ * @memberOf _
+ * @category Math
+ * @param {number} n The number to round up.
+ * @param {number} [precision=0] The precision to round up to.
+ * @returns {number} Returns the rounded up number.
+ * @example
+ *
+ * _.ceil(4.006);
+ * // => 5
+ *
+ * _.ceil(6.004, 2);
+ * // => 6.01
+ *
+ * _.ceil(6040, -2);
+ * // => 6100
+ */
+var ceil = createRound('ceil');
+
+export default ceil;

math/floor.js

@@ -0,0 +1,25 @@
+import createRound from '../internal/createRound';
+
+/**
+ * Calculates `n` rounded down to `precision`.
+ *
+ * @static
+ * @memberOf _
+ * @category Math
+ * @param {number} n The number to round down.
+ * @param {number} [precision=0] The precision to round down to.
+ * @returns {number} Returns the rounded down number.
+ * @example
+ *
+ * _.floor(4.006);
+ * // => 4
+ *
+ * _.floor(0.046, 2);
+ * // => 0.04
+ *
+ * _.floor(4060, -2);
+ * // => 4000
+ */
+var floor = createRound('floor');
+
+export default floor;

math/round.js

@@ -0,0 +1,25 @@
+import createRound from '../internal/createRound';
+
+/**
+ * Calculates `n` rounded to `precision`.
+ *
+ * @static
+ * @memberOf _
+ * @category Math
+ * @param {number} n The number to round.
+ * @param {number} [precision=0] The precision to round to.
+ * @returns {number} Returns the rounded number.
+ * @example
+ *
+ * _.round(4.006);
+ * // => 4
+ *
+ * _.round(4.006, 2);
+ * // => 4.01
+ *
+ * _.round(4060, -2);
+ * // => 4100
+ */
+var round = createRound('round');
+
+export default round;

math/sum.js

@@ -39,13 +39,11 @@ import toIterable from '../internal/toIterable';
  */
 function sum(collection, iteratee, thisArg) {
   if (thisArg && isIterateeCall(collection, iteratee, thisArg)) {
-    iteratee = null;
+    iteratee = undefined;
   }
-  var noIteratee = iteratee == null;
-
-  iteratee = noIteratee ? iteratee : baseCallback(iteratee, thisArg, 3);
-  return noIteratee
-    ? arraySum(isArray(collection) ? collection : toIterable(collection))
+  iteratee = baseCallback(iteratee, thisArg, 3);
+  return iteratee.length == 1
+    ? arraySum(isArray(collection) ? collection : toIterable(collection), iteratee)
     : baseSum(collection, iteratee);
 }
 

number/inRange.js

@@ -35,7 +35,7 @@ var nativeMax = Math.max,
  */
 function inRange(value, start, end) {
   start = +start || 0;
-  if (typeof end === 'undefined') {
+  if (end === undefined) {
     end = start;
     start = 0;
   } else {

number/random.js

@@ -34,7 +34,7 @@ var nativeMin = Math.min,
  */
 function random(min, max, floating) {
   if (floating && isIterateeCall(min, max, floating)) {
-    max = floating = null;
+    max = floating = undefined;
   }
   var noMin = min == null,
       noMax = max == null;