2 // https://github.com/tc39/proposal-iterator-helpers
3 var $ = require('../internals/export');
4 var call = require('../internals/function-call');
5 var aCallable = require('../internals/a-callable');
6 var anObject = require('../internals/an-object');
7 var createAsyncIteratorProxy = require('../internals/async-iterator-create-proxy');
8 var getAsyncIterator = require('../internals/get-async-iterator');
10 var AsyncIteratorProxy = createAsyncIteratorProxy(function (Promise) {
12 var mapper = state.mapper;
15 return new Promise(function (resolve, reject) {
16 var outerLoop = function () {
18 Promise.resolve(anObject(call(state.next, state.iterator))).then(function (step) {
20 if (anObject(step).done) {
22 resolve({ done: true, value: undefined });
24 Promise.resolve(mapper(step.value)).then(function (mapped) {
26 state.innerIterator = innerIterator = getAsyncIterator(mapped);
27 state.innerNext = aCallable(innerIterator.next);
29 } catch (error2) { reject(error2); }
32 } catch (error1) { reject(error1); }
34 } catch (error) { reject(error); }
37 var innerLoop = function () {
38 if (innerIterator = state.innerIterator) {
40 Promise.resolve(anObject(call(state.innerNext, innerIterator))).then(function (result) {
42 if (anObject(result).done) {
43 state.innerIterator = state.innerNext = null;
45 } else resolve({ done: false, value: result.value });
46 } catch (error1) { reject(error1); }
48 } catch (error) { reject(error); }
56 $({ target: 'AsyncIterator', proto: true, real: true }, {
57 flatMap: function flatMap(mapper) {
58 return new AsyncIteratorProxy({
59 iterator: anObject(this),
60 mapper: aCallable(mapper),