| 'use strict'; |
| var ctx = require('./_ctx') |
| , $export = require('./_export') |
| , toObject = require('./_to-object') |
| , call = require('./_iter-call') |
| , isArrayIter = require('./_is-array-iter') |
| , toLength = require('./_to-length') |
| , createProperty = require('./_create-property') |
| , 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) |
| , C = typeof this == 'function' ? this : Array |
| , aLen = arguments.length |
| , mapfn = aLen > 1 ? arguments[1] : undefined |
| , mapping = mapfn !== undefined |
| , index = 0 |
| , iterFn = getIterFn(O) |
| , 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; |
| } |
| }); |
