'use strict'; var global = require('../internals/global'); var isArray = require('../internals/is-array'); var lengthOfArrayLike = require('../internals/length-of-array-like'); var bind = require('../internals/function-bind-context'); var TypeError = global.TypeError; // `FlattenIntoArray` abstract operation // https://tc39.github.io/proposal-flatMap/#sec-FlattenIntoArray var flattenIntoArray = function (target, original, source, sourceLen, start, depth, mapper, thisArg) { var targetIndex = start; var sourceIndex = 0; var mapFn = mapper ? bind(mapper, thisArg) : false; var element, elementLen; while (sourceIndex < sourceLen) { if (sourceIndex in source) { element = mapFn ? mapFn(source[sourceIndex], sourceIndex, original) : source[sourceIndex]; if (depth > 0 && isArray(element)) { elementLen = lengthOfArrayLike(element); targetIndex = flattenIntoArray(target, original, element, elementLen, targetIndex, depth - 1) - 1; } else { if (targetIndex >= 0x1FFFFFFFFFFFFF) throw TypeError('Exceed the acceptable array length'); target[targetIndex] = element; } targetIndex++; } sourceIndex++; } return targetIndex; }; module.exports = flattenIntoArray;