bluebird

问题 Could someone help me understand the differences between using Koa.js and Bluebird.js with ES6 Harmony. Specifically, how does co( function * () { //stuff } ); compare to, Promise.coroutine( function * () { //stuff } ); It just seems Koa should be using Bluebird and not recreating the wheel. What's different? 回答1: For now the difference is that Koa allows yielding more than just promises. However a feature is being added that allows not only yielding callbacks, thunks etc but any arbitrary

问题 Closed . This question needs details or clarity. It is not currently accepting answers. Want to improve this question? Add details and clarify the problem by editing this post. Closed 4 years ago . I have an array that contains filenames at each index. I want to download those files one at a time (synchronously). I know about ' Async ' module. But I want to know whether any functions in Lodash or Underscore or Bluebird library supports this functionality. 回答1: You can use bluebird's Promise

问题 We would like to reduce the number of catch blocks inside our promises. If we remove the nested catches, will exceptions bubble up to the parent catch? temporaryUserModel.findOne({email: req.body.email}) .then(tempUser => { if (tempUser) { temporaryUserModel.findOneAndUpdate({_id: tempUser.toJSON()._id}, user) .then((doc) => { return res.status(200).json({ status: 'Success', data: {url: planOpted.chargifySignupUrl} }); }) .catch(err => error(err, res)); } else { temporaryUserModel(user).save(

问题 I am new super new to Promises and Node and am curious about using promises with streams. Can I promisify a stream? Using Bluebirdjs and the Twit module I have the following: var Twit = require('twit') var Promise = require("bluebird"); var T = new Twit({ consumer_key: process.env.CONSUMER_KEY, consumer_secret: process.env.CONSUMER_SECRET, access_token: process.env.ACCESS_TOKEN, access_token_secret: process.env.ACCESS_TOKEN_SECRET }) Promise.promisifyAll(Twit); Promise.promisifyAll(T); var

问题 Closed . This question needs details or clarity. It is not currently accepting answers. Want to improve this question? Add details and clarify the problem by editing this post. Closed 5 years ago . I want a promise that waits until then is called before it runs. That is, if I never actually call then , the promise will never run. Is this possible? 回答1: Make a function which creates and returns a promise on first invocation, but returns the same promise on each subsequent invocation: function

问题 I don't necessarily want to error, but I have: getFromDb().then (tradeData) -> if not tradeData # DO NOT CONTINUE THE CHAIN else getLatestPrice tradeData .then (latestPrice) -> ... .then -> ... .then -> ... .catch (err) -> next err Any way for me to abort the chain if there is no tradeData? 回答1: getFromDb().then (tradeData) -> if tradeData getLatestPrice tradeData -> .then (latestPrice) -> ... .then -> ... .then -> ... .catch (err) -> next err else getSomethingElse -> send("no data") In 3.0,

问题 I'm using Node.js and Bluebird to create some fairly complicated logic involving uncompressing a structured file, parsing JSON, creating and making changes to several MongoDB documents, and writing related files in multiple locations. I also have fairly complicated error handling for all of this depending on the state of the system when an error occurs. I am having difficulty thinking of a good way to manage dependencies through the flow of promises. My existing code basically looks like this

问题 I have a promise that returns data and I want to save that in variables. Is this impossible in JavaScript because of the async nature and do I need to use onResolve as a callback? Can I somehow use this (e.g. wrap it with async/await): const { foo, bar } = Promise.then(result => result.data, errorHandler); // rest of script instead of this? Promise.then(result => { const { foo, bar } = result.data; // rest of script }, errorHandler); Note: Bluebird library is used instead of native

问题 I have a custom error class: class NetworkError extends Error { constructor() { super('Network Error'); this.name = 'NetworkError'; } } And I want to handle it specifically: import {NetworkError} from '../../common/errors'; someFunc().catch(NetworkError, err => { // this is missed }).catch(err => { // this is hit }); But it's skipping my custom catch and hitting the general catch. If I change it like so, it works: someFunc().catch({name: 'NetworkError'}, err => { // this is hit }).catch(err =

问题 I'm in the process of replacing some old code that used jQuery Deferred objects and I am rewriting using Bluebird/ES6 Promises. If I have multiple asynchronous calls, how can I trigger a function after all the promises are resolved. Using jQuery Deferreds it would be something like this: var requests = [...]; //some arbitrary data that is iterated to generate multiple ajax requests var promises = []; resuests.forEach(function(endpoint) { promises.push($.ajax({url: endpoint})); }); $.when