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'use strict'
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/**
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* Expose `arrayFlatten`.
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*/
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module.exports = arrayFlatten
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/**
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* Recursive flatten function with depth.
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*
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* @param {Array} array
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* @param {Array} result
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* @param {Number} depth
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* @return {Array}
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*/
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function flattenWithDepth (array, result, depth) {
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for (var i = 0; i < array.length; i++) {
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var value = array[i]
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if (depth > 0 && Array.isArray(value)) {
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flattenWithDepth(value, result, depth - 1)
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} else {
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result.push(value)
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}
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}
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return result
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}
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/**
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* Recursive flatten function. Omitting depth is slightly faster.
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*
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* @param {Array} array
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* @param {Array} result
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* @return {Array}
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*/
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function flattenForever (array, result) {
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for (var i = 0; i < array.length; i++) {
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var value = array[i]
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if (Array.isArray(value)) {
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flattenForever(value, result)
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} else {
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result.push(value)
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}
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}
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return result
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}
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/**
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* Flatten an array, with the ability to define a depth.
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*
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* @param {Array} array
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* @param {Number} depth
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* @return {Array}
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*/
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function arrayFlatten (array, depth) {
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if (depth == null) {
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return flattenForever(array, [])
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}
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return flattenWithDepth(array, [], depth)
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}
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