2 // https://github.com/tc39/proposal-iterator-helpers
3 var $ = require('../internals/export');
4 var aFunction = require('../internals/a-function');
5 var anObject = require('../internals/an-object');
6 var createIteratorProxy = require('../internals/iterator-create-proxy');
7 var callWithSafeIterationClosing = require('../internals/call-with-safe-iteration-closing');
9 var IteratorProxy = createIteratorProxy(function (arg) {
10 var iterator = this.iterator;
11 var filterer = this.filterer;
13 var result, done, value;
15 result = anObject(next.call(iterator, arg));
16 done = this.done = !!result.done;
19 if (callWithSafeIterationClosing(iterator, filterer, value)) return value;
23 $({ target: 'Iterator', proto: true, real: true }, {
24 filter: function filter(filterer) {
25 return new IteratorProxy({
26 iterator: anObject(this),
27 filterer: aFunction(filterer)