| 'use strict'; |
| // https://github.com/tc39/proposal-iterator-helpers |
| var $ = require('../internals/export'); |
| var aFunction = require('../internals/a-function'); |
| var anObject = require('../internals/an-object'); |
| var createIteratorProxy = require('../internals/create-iterator-proxy'); |
| var callWithSafeIterationClosing = require('../internals/call-with-safe-iteration-closing'); |
| |
| var IteratorProxy = createIteratorProxy(function (arg) { |
| var iterator = this.iterator; |
| var filterer = this.filterer; |
| var next = this.next; |
| var result, done, value; |
| while (true) { |
| result = anObject(next.call(iterator, arg)); |
| done = this.done = !!result.done; |
| if (done) return; |
| value = result.value; |
| if (callWithSafeIterationClosing(iterator, filterer, value)) return value; |
| } |
| }); |
| |
| $({ target: 'Iterator', proto: true, real: true }, { |
| filter: function filter(filterer) { |
| return new IteratorProxy({ |
| iterator: anObject(this), |
| filterer: aFunction(filterer) |
| }); |
| } |
| }); |