| | |
| | | 'use strict'; |
| | | var global = require('../internals/global'); |
| | | var bind = require('../internals/function-bind-context'); |
| | | var call = require('../internals/function-call'); |
| | | var toObject = require('../internals/to-object'); |
| | | var callWithSafeIterationClosing = require('../internals/call-with-safe-iteration-closing'); |
| | | var isArrayIteratorMethod = require('../internals/is-array-iterator-method'); |
| | |
| | | var getIterator = require('../internals/get-iterator'); |
| | | var getIteratorMethod = require('../internals/get-iterator-method'); |
| | | |
| | | var Array = global.Array; |
| | | |
| | | // `Array.from` method implementation |
| | | // https://tc39.es/ecma262/#sec-array.from |
| | | module.exports = function from(arrayLike /* , mapfn = undefined, thisArg = undefined */) { |
| | |
| | | var argumentsLength = arguments.length; |
| | | var mapfn = argumentsLength > 1 ? arguments[1] : undefined; |
| | | var mapping = mapfn !== undefined; |
| | | if (mapping) mapfn = bind(mapfn, argumentsLength > 2 ? arguments[2] : undefined, 2); |
| | | if (mapping) mapfn = bind(mapfn, argumentsLength > 2 ? arguments[2] : undefined); |
| | | var iteratorMethod = getIteratorMethod(O); |
| | | var index = 0; |
| | | var length, result, step, iterator, next, value; |
| | |
| | | iterator = getIterator(O, iteratorMethod); |
| | | next = iterator.next; |
| | | result = IS_CONSTRUCTOR ? new this() : []; |
| | | for (;!(step = next.call(iterator)).done; index++) { |
| | | for (;!(step = call(next, iterator)).done; index++) { |
| | | value = mapping ? callWithSafeIterationClosing(iterator, mapfn, [step.value, index], true) : step.value; |
| | | createProperty(result, index, value); |
| | | } |