32 lines
1.1 KiB
JavaScript
32 lines
1.1 KiB
JavaScript
'use strict';
|
|
var isArray = require('../internals/is-array');
|
|
var toLength = require('../internals/to-length');
|
|
var bind = require('../internals/function-bind-context');
|
|
|
|
// `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, 3) : false;
|
|
var element;
|
|
|
|
while (sourceIndex < sourceLen) {
|
|
if (sourceIndex in source) {
|
|
element = mapFn ? mapFn(source[sourceIndex], sourceIndex, original) : source[sourceIndex];
|
|
|
|
if (depth > 0 && isArray(element)) {
|
|
targetIndex = flattenIntoArray(target, original, element, toLength(element.length), 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;
|