2 // https://github.com/tc39/proposal-iterator-helpers
3 var $ = require('../internals/export');
4 var anObject = require('../internals/an-object');
5 var createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy');
7 var AsyncIteratorProxy = createAsyncIteratorProxy(function (arg, Promise) {
9 var iterator = state.iterator;
11 return Promise.resolve(anObject(state.next.call(iterator, arg))).then(function (step) {
12 if (anObject(step).done) {
14 return { done: true, value: undefined };
16 return { done: false, value: [state.index++, step.value] };
20 $({ target: 'AsyncIterator', proto: true, real: true }, {
21 asIndexedPairs: function asIndexedPairs() {
22 return new AsyncIteratorProxy({
23 iterator: anObject(this),