Source: \reduce.js
import arrayReduce from './.internal/arrayReduce.js'
import baseEach from './.internal/baseEach.js'
import baseReduce from './.internal/baseReduce.js'
/**
* Reduces `collection` to a value which is the accumulated result of running
* each element in `collection` thru `iteratee`, where each successive
* invocation is supplied the return value of the previous. If `accumulator`
* is not given, the first element of `collection` is used as the initial
* value. The iteratee is 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`, `orderBy`,
* and `sortBy`
*
* @since 0.1.0
* @category Collection
* @param {Array|Object} collection The collection to iterate over.
* @param {Function} iteratee The function invoked per iteration.
* @param {*} [accumulator] The initial value.
* @returns {*} Returns the accumulated value.
* @see reduceRight, transform
* @example
*
* reduce([1, 2], (sum, n) => sum + n, 0)
* // => 3
*
* reduce({ 'a': 1, 'b': 2, 'c': 1 }, (result, value, key) => {
* (result[value] || (result[value] = [])).push(key)
* return result
* }, {})
* // => { '1': ['a', 'c'], '2': ['b'] } (iteration order is not guaranteed)
*/
function reduce(collection, iteratee, accumulator) {
const func = Array.isArray(collection) ? arrayReduce : baseReduce
const initAccum = arguments.length < 3
return func(collection, iteratee, accumulator, initAccum, baseEach)
}
export default reduce