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JavaScript

var arrayReduce = require('../internal/arrayReduce'),
baseEach = require('../internal/baseEach'),
createReduce = require('../internal/createReduce');
/**
* Reduces `collection` to a value which is the accumulated result of running
* each element in `collection` through `iteratee`, where each successive
* invocation is supplied the return value of the previous. If `accumulator`
* is not provided the first element of `collection` is used as the initial
* value. The `iteratee` is bound to `thisArg` and invoked with four arguments:
* (accumulator, value, index|key, collection).
*
* Many lodash methods are guarded to work as iteratees for methods like
* `_.reduce`, `_.reduceRight`, and `_.transform`.
*
* The guarded methods are:
* `assign`, `defaults`, `defaultsDeep`, `includes`, `merge`, `sortByAll`,
* and `sortByOrder`
*
* @static
* @memberOf _
* @alias foldl, inject
* @category Collection
* @param {Array|Object|string} collection The collection to iterate over.
* @param {Function} [iteratee=_.identity] The function invoked per iteration.
* @param {*} [accumulator] The initial value.
* @param {*} [thisArg] The `this` binding of `iteratee`.
* @returns {*} Returns the accumulated value.
* @example
*
* _.reduce([1, 2], function(total, n) {
* return total + n;
* });
* // => 3
*
* _.reduce({ 'a': 1, 'b': 2 }, function(result, n, key) {
* result[key] = n * 3;
* return result;
* }, {});
* // => { 'a': 3, 'b': 6 } (iteration order is not guaranteed)
*/
var reduce = createReduce(arrayReduce, baseEach);
module.exports = reduce;