| 'use strict'; |
| var ctx = require('./_ctx'); |
| var $export = require('./_export'); |
| var toObject = require('./_to-object'); |
| var call = require('./_iter-call'); |
| var isArrayIter = require('./_is-array-iter'); |
| var toLength = require('./_to-length'); |
| var createProperty = require('./_create-property'); |
| var getIterFn = require('./core.get-iterator-method'); |
| |
| $export($export.S + $export.F * !require('./_iter-detect')(function (iter) { Array.from(iter); }), 'Array', { |
| // 22.1.2.1 Array.from(arrayLike, mapfn = undefined, thisArg = undefined) |
| from: function from(arrayLike /* , mapfn = undefined, thisArg = undefined */) { |
| var O = toObject(arrayLike); |
| var C = typeof this == 'function' ? this : Array; |
| var aLen = arguments.length; |
| var mapfn = aLen > 1 ? arguments[1] : undefined; |
| var mapping = mapfn !== undefined; |
| var index = 0; |
| var iterFn = getIterFn(O); |
| var length, result, step, iterator; |
| if (mapping) mapfn = ctx(mapfn, aLen > 2 ? arguments[2] : undefined, 2); |
| // if object isn't iterable or it's array with default iterator - use simple case |
| if (iterFn != undefined && !(C == Array && isArrayIter(iterFn))) { |
| for (iterator = iterFn.call(O), result = new C(); !(step = iterator.next()).done; index++) { |
| createProperty(result, index, mapping ? call(iterator, mapfn, [step.value, index], true) : step.value); |
| } |
| } else { |
| length = toLength(O.length); |
| for (result = new C(length); length > index; index++) { |
| createProperty(result, index, mapping ? mapfn(O[index], index) : O[index]); |
| } |
| } |
| result.length = index; |
| return result; |
| } |
| }); |