2 // https://github.com/tc39/proposal-iterator-helpers
3 var $ = require('../internals/export');
4 var apply = require('../internals/function-apply');
5 var aCallable = require('../internals/a-callable');
6 var anObject = require('../internals/an-object');
7 var createIteratorProxy = require('../internals/iterator-create-proxy');
8 var callWithSafeIterationClosing = require('../internals/call-with-safe-iteration-closing');
10 var IteratorProxy = createIteratorProxy(function (args) {
11 var iterator = this.iterator;
12 var filterer = this.filterer;
14 var result, done, value;
16 result = anObject(apply(next, iterator, args));
17 done = this.done = !!result.done;
20 if (callWithSafeIterationClosing(iterator, filterer, value)) return value;
24 $({ target: 'Iterator', proto: true, real: true }, {
25 filter: function filter(filterer) {
26 return new IteratorProxy({
27 iterator: anObject(this),
28 filterer: aCallable(filterer)