12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849 |
- 'use strict';
- // https://github.com/tc39/proposal-iterator-helpers
- var $ = require('../internals/export');
- var global = require('../internals/global');
- var call = require('../internals/function-call');
- var aCallable = require('../internals/a-callable');
- var anObject = require('../internals/an-object');
- var getBuiltIn = require('../internals/get-built-in');
- var Promise = getBuiltIn('Promise');
- var TypeError = global.TypeError;
- $({ target: 'AsyncIterator', proto: true, real: true, forced: true }, {
- reduce: function reduce(reducer /* , initialValue */) {
- var iterator = anObject(this);
- var next = aCallable(iterator.next);
- var noInitial = arguments.length < 2;
- var accumulator = noInitial ? undefined : arguments[1];
- aCallable(reducer);
- return new Promise(function (resolve, reject) {
- var loop = function () {
- try {
- Promise.resolve(anObject(call(next, iterator))).then(function (step) {
- try {
- if (anObject(step).done) {
- noInitial ? reject(TypeError('Reduce of empty iterator with no initial value')) : resolve(accumulator);
- } else {
- var value = step.value;
- if (noInitial) {
- noInitial = false;
- accumulator = value;
- loop();
- } else {
- Promise.resolve(reducer(accumulator, value)).then(function (result) {
- accumulator = result;
- loop();
- }, reject);
- }
- }
- } catch (err) { reject(err); }
- }, reject);
- } catch (error) { reject(error); }
- };
- loop();
- });
- }
- });
|