| 'use strict'; |
| // https://github.com/tc39/proposal-iterator-helpers |
| var $ = require('../internals/export'); |
| var aFunction = require('../internals/a-function'); |
| var anObject = require('../internals/an-object'); |
| var isObject = require('../internals/is-object'); |
| var createAsyncIteratorProxy = require('../internals/create-async-iterator-proxy'); |
| var getAsyncIteratorMethod = require('../internals/get-async-iterator-method'); |
| |
| var AsyncIteratorProxy = createAsyncIteratorProxy(function (arg, Promise) { |
| var state = this; |
| var mapper = state.mapper; |
| var innerIterator, iteratorMethod; |
| |
| return new Promise(function (resolve, reject) { |
| var outerLoop = function () { |
| try { |
| Promise.resolve(anObject(state.next.call(state.iterator, arg))).then(function (step) { |
| try { |
| if (anObject(step).done) { |
| state.done = true; |
| resolve({ done: true, value: undefined }); |
| } else { |
| Promise.resolve(mapper(step.value)).then(function (mapped) { |
| try { |
| if (isObject(mapped) && (iteratorMethod = getAsyncIteratorMethod(mapped)) !== undefined) { |
| state.innerIterator = innerIterator = iteratorMethod.call(mapped); |
| state.innerNext = aFunction(innerIterator.next); |
| return innerLoop(); |
| } resolve({ done: false, value: mapped }); |
| } catch (error2) { reject(error2); } |
| }, reject); |
| } |
| } catch (error1) { reject(error1); } |
| }, reject); |
| } catch (error) { reject(error); } |
| }; |
| |
| var innerLoop = function () { |
| if (innerIterator = state.innerIterator) { |
| try { |
| Promise.resolve(anObject(state.innerNext.call(innerIterator))).then(function (result) { |
| try { |
| if (anObject(result).done) { |
| state.innerIterator = state.innerNext = null; |
| outerLoop(); |
| } else resolve({ done: false, value: result.value }); |
| } catch (error1) { reject(error1); } |
| }, reject); |
| } catch (error) { reject(error); } |
| } else outerLoop(); |
| }; |
| |
| innerLoop(); |
| }); |
| }); |
| |
| $({ target: 'AsyncIterator', proto: true, real: true }, { |
| flatMap: function flatMap(mapper) { |
| return new AsyncIteratorProxy({ |
| iterator: anObject(this), |
| mapper: aFunction(mapper), |
| innerIterator: null, |
| innerNext: null |
| }); |
| } |
| }); |