| 'use strict'; |
| // https://github.com/tc39/proposal-iterator-helpers |
| var $ = require('../internals/export'); |
| var anObject = require('../internals/an-object'); |
| var toPositiveInteger = require('../internals/to-positive-integer'); |
| var createAsyncIteratorProxy = require('../internals/create-async-iterator-proxy'); |
| |
| var AsyncIteratorProxy = createAsyncIteratorProxy(function (arg, Promise) { |
| var state = this; |
| |
| return new Promise(function (resolve, reject) { |
| var loop = function () { |
| try { |
| Promise.resolve( |
| anObject(state.next.call(state.iterator, state.remaining ? undefined : arg)) |
| ).then(function (step) { |
| try { |
| if (anObject(step).done) { |
| state.done = true; |
| resolve({ done: true, value: undefined }); |
| } else if (state.remaining) { |
| state.remaining--; |
| loop(); |
| } else resolve({ done: false, value: step.value }); |
| } catch (err) { reject(err); } |
| }, reject); |
| } catch (error) { reject(error); } |
| }; |
| |
| loop(); |
| }); |
| }); |
| |
| $({ target: 'AsyncIterator', proto: true, real: true }, { |
| drop: function drop(limit) { |
| return new AsyncIteratorProxy({ |
| iterator: anObject(this), |
| remaining: toPositiveInteger(limit) |
| }); |
| } |
| }); |