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Optimize _.reduce and _.reduceRight.

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John-David Dalton
2014-06-30 21:24:07 -07:00
parent afcf539e6e
commit 464691f129
1 changed files with 36 additions and 19 deletions
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55
lodash.js
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@@ -1179,6 +1179,30 @@
return accumulator;
}
/**
* A specialized version of `_.reduceRight` for arrays without support for
* callback shorthands or `this` binding.
*
* @private
* @param {Array} array The array to iterate over.
* @param {Function} iterator The function called per iteration.
* @param {*} [accumulator] The initial value.
* @param {boolean} [initFromArray=false] Specify using the first element of
* `array` as the initial value.
* @returns {*} Returns the accumulated value.
*/
function arrayReduceRight(array, iterator, accumulator, initFromArray) {
var length = array.length;
if (initFromArray && length) {
accumulator = array[--length];
}
while (length--) {
accumulator = iterator(accumulator, array[length], length, array);
}
return accumulator;
}
/**
* A specialized version of `_.some` for arrays without support for callback
* shorthands or `this` binding.
@@ -1676,7 +1700,7 @@
* @private
* @param {Array|Object|string} collection The collection to search.
* @param {Function} predicate The function called per iteration.
* @param {Function} eachFunc The function to iterate over the collection.
* @param {Function} eachFunc The function to iterate over `collection`.
* @param {boolean} [retKey=false] Specify returning the key of the found
* element instead of the element itself.
* @returns {*} Returns the found element or its key, else `undefined`.
@@ -2239,19 +2263,21 @@
}
/**
* The base implementation of `_.reduce` without support for callback
* shorthands or `this` binding.
* The base implementation of `_.reduce` and `_.reduceRight` without support
* for callback shorthands or `this` binding, which iterates over `collection`
* usingthe provided `eachFunc`.
*
* @private
* @param {Array|Object|string} collection The collection to iterate over.
* @param {Function} iterator The function called per iteration.
* @param {*} [accumulator] The initial value.
* @param {boolean} [initFromCollection=false] Specify using the first element
* @param {*} accumulator The initial value.
* @param {boolean} initFromCollection Specify using the first element
* of `collection` as the initial value.
* @param {Function} eachFunc The function to iterate over `collection`.
* @returns {*} Returns the accumulated value.
*/
function baseReduce(collection, iterator, accumulator, initFromCollection) {
baseEach(collection, function(value, index, collection) {
function baseReduce(collection, iterator, accumulator, initFromCollection, eachFunc) {
eachFunc(collection, function(value, index, collection) {
accumulator = initFromCollection
? (initFromCollection = false, value)
: iterator(accumulator, value, index, collection)
@@ -5066,10 +5092,8 @@
* // => { 'a': 3, 'b': 6, 'c': 9 }
*/
function reduce(collection, iterator, accumulator, thisArg) {
iterator = lodash.callback(iterator, thisArg, 4);
var func = isArray(collection) ? arrayReduce : baseReduce;
return func(collection, iterator, accumulator, arguments.length < 3);
return func(collection, lodash.callback(iterator, thisArg, 4), accumulator, arguments.length < 3, baseEach);
}
/**
@@ -5092,15 +5116,8 @@
* // => [4, 5, 2, 3, 0, 1]
*/
function reduceRight(collection, iterator, accumulator, thisArg) {
var initFromCollection = arguments.length < 3;
iterator = lodash.callback(iterator, thisArg, 4);
baseEachRight(collection, function(value, index, collection) {
accumulator = initFromCollection
? (initFromCollection = false, value)
: iterator(accumulator, value, index, collection);
});
return accumulator;
var func = isArray(collection) ? arrayReduceRight : baseReduce;
return func(collection, lodash.callback(iterator, thisArg, 4), accumulator, arguments.length < 3, baseEachRight);
}
/**