Questions tagged [promise]
"Promises" are a particular tactic for deferred computing, suitable for several styles of concurrency: thread and event loop concurrency for local computation, and both synchronous and asynchronous remote messaging.
251
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Bluebird: promisify xhr request
I use bluebird promises. I want to promisify my requests from communication layer:
Utils.js
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2
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1
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Async db repository
This is a simple repository where I want to save all the invoices of some queried users. I wanted this module to only expose a simple saveInvoices method and return ...
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Caching/memoizing promise results
I'm wondering what the best approach might be.
One approach is to chain cachedPromise and "regular", thus, if cachedPromise ...
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1
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Access resolve function outside of a JavaScript Promise
I have an object that needs to have a single point of initialization, and other callers need to wait until the initialization is complete before continuing.
I have done this with jQuery, and it feels ...
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3
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Save handler without a nested "deferred antipattern"
I have an application in which a user makes a change, and when they click Save they will be prompted to confirm, and the appropriate REST call will be made if they agree. The intial call to ...
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0
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Flux & async communication with websockets
I want to arrange async server-client communication with websockets and vanilla flux architecture. There is an excellent article about "Async Server-Side Communication with the Flux Architecture". I ...
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NodeJS broker between MongoDB and RabbitMQ
I wrote a small program that aims to take some data from the MongoDB database and put them in the RabbitMQ queue.
I tried to use only promise style but I am a beginner in JavaScript. Could you please ...
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2
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Unit testing a click event with asynchronous content
I'm writing unit tests for a web application that has quite a lot of UI interactions. I would like some feedback regarding on how to handle click events with asynchronous code.
My goal here is to ...
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File existence promise
I hate to have to write a custom exists promise every time I need to know if a file exists, so I came up with this. Thoughts?
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1
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Deleting a section of a website using Ajax
I am currently writing a decent amount of ajax to help me delete a section of a website.
It's already becoming a pretty big piece of code, I wondered if it were possible to compact a section of my ...
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1
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Flow of Angular Promises
I recently put in a submission for a small coding challenge using Angular. The challenge was to get a token and array of values using a GET request then make another GET request passing the token and ...
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Promise.jsm demo of Promise.all and Promise.defer
I created this demo example for MDN documentation to show how to use Promise.all and Promise.defer in user created promise. I ...
CommunityBot
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Taking and saving pictures using promises
I have the following 4 functions that work, however, I am sure that utilising promises will improve my code. I just find them so confusing.
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Java 8 CompletableFuture - fan out implementation
I was wondering what is the best way to implement a fan out type of functionality with Java 8 Completable future. I recently rewrote a function that had a bunch of old ...
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Mongoose and Hapi/Express promise handling in controllers
I'm switching my code to promises - mostly as delivered by Mongoose. I use Hapi though I think something similar would apply to Express.
In my models/services I perform queries such as:
...
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2
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0
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509
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NodeJS authentication function rewrite with promises
I will post both of the modules, some of the code in them may be "irrelevant" for the main concern here, which is Security.prototype.authenticate(). Nevertheless, comments are welcome about all of the ...
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1
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Two dialog boxes using Deferreds?
I've two similar functions and I want to use one generic function with two params, dialog and buttons. How do I do it?
My ...
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1
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4k
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Angular Broadcast Asynchronous Events
Okay I have the following use case:
Module A broadcasts an event.
Module B listens to that event.
Maybe also ...
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1
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27k
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Use Promise to wait until DOM element exists
I need to create a JavaScript Promise that will not resolve until a specific HTML element is loaded on the page.
I don't have any way of knowing when this element will be loaded, other than to simply ...
- 144k
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1
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Detecting gyroscope data using promises
In a plugin that I am currently authoring, I am using a function to check whether the device provides gyroscopic data. Although intuitively this can be easily resolved by checking the value of ...
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1
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Logging out using nested promises
Is it OK to do that ?
for example, I have my log out service
...
- 144k
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0
answers
132
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Q.js worker pool
I'm building a program to scrape data about hockey games in order to compile statistics. One of the run modes will process all of the games in a single season (1230). Processing a single game consists ...
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1
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Validate IP address and create a registration attempt
I'm a C++/Python developer attempting to learn JavaScript, but I'm struggling to write clean code. I've read that async.waterfall and Promises are two ways to flatten the code a bit, but my ...
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1
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Fetching ALL data set from API iterating via response data
Does this make sense? How would you achieve the same thing, with cleaner code?
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1
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Using $q in Angular JS to pass navigator geo JSON from factory to controller
This code is used to get the users location and deliver it as a resource to the controller. The aim is to have this data shared across multiple controllers in the application. So far this does deliver ...
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0
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Rewriting authentication controller using promises
I am in the process of refactoring some complex code that uses callbacks to instead use promises. I am trying to figure out if my proposed approaches make sense.
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2
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1
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Promise-driven animation
Inspired by this question on Stack Overflow, I've attempted to code such animation, mostly to get some more practice with async, promises and Q.js:
(Live demo)
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1
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Using the $q service in AngularJS to handle promises
I have a service which needs to store some settings data in a DB and at the same time maintain a reference to that in the user'slocalStorage (we want two users ...
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1
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Checking for JSON or YAML file with promises
I'm using bluebird promises. I'm converting fs.exists to existsAsync (here's how) and ...
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1
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15k
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Simple Async Google Maps initializer with AngularJS
Here is a simple reusable AngularJS factory I came up with to initialize Google Maps Asynchronously, which somehow does not seem ...
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1
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4k
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NodeJS and Express with Promises
I'm relatively new to NodeJS and Express, and I've recently run into the pyramid of Doom while doing stuff that requires multiple steps.
I've found that promises are very promising indeed. But I ...
- 33.2k
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2
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Implementing JQuery style 'deferred' and 'promise' in C#
I like the pattern of the jQuery Deferred object.
I like how you can call Resolve any number of times, but the listening objects will only be notified once. I also ...
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0
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1
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Make sequential fadeIn() promises more manageable
I've two versions of promise code. The page is a simple one - an unordered list with a few items. I am trying to make the items show up (fadeIn) one-after-another ...
- 25k
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Reading the contents at three URLs using Promises
I'm learning promises and now I'm trying to figure out if something in this code can be improved. This code is expected 3 urls and then async parallel calls should be done. When all requests are ...
- 33.2k
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Using a Wrapper Promise
I wrote some code for an application that uses the following pattern:
...
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1
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490
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Pledge: Promise-like entities design goals experiment
Background
I was writing a promises/a+ implementation, just for fun. About halfway through I decided it wasn't that fun after all, so I decided to do something a little different.
Thinking of ...
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2
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1
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226
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Pyramidal promises
I have a situation in my Node (express) controller where I need to check whether a particular language has a parent language, if it does, I need to do a new DB (SQL) call to retrieve the parent ...
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1
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My yld NPM - callbacks/promises alternative
I'd like feedback on my callbacks/promises alternative, please.
The yld repository
...
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1
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377
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Testing Promises vs Lock performance
I'm not sure if my lock usage is correct and safe. I wanted to know what will be best approach to deal with situation when one thread have to wait for being initialized by another so I written this ...
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vote
2
answers
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Promises and chained calls
I've realized JS callback hell and I started looking into Promises libraries.
After reading some articles I decided to start with BluebirdJS. I didn't realise how to properly use them yet, because ...
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1
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Is this a reasonable way to implement promises in node.js?
I'm using passport to setup login in an express site. The site is just a playground for me to learn. The code inside login was exhibiting the arrow anti pattern so I decided it was time to learn to ...
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1
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691
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Angular promise in service
I'm new with Angular promise and I would like to know how to improve my code.
I have a service which preload media or data by calling an API.
The media API return an array of urls to preload.
...
- 33.2k
2
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1
answer
267
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Thoughts on this conversion of code from Step.js to Q promise library?
I have some code that I'd written using this pattern with Step.js. In this case, talking to MongoDB in Node:
...
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1
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Structuring functions receiving and returning promises?
I keep running into the same pattern with code using promises in javascript.
When writing a function which takes a promise and returns a promise, obviously I want to reject the promise I'm returning ...
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1
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1k
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Limiting Q promise concurrency in JavaScript
I wrote a helper to limit Q promise concurrency.
If I have a promise-returning function promiseSomething, writing
...
- 146
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votes
2
answers
210
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Refactoring asynchronous JS pre-rendering code
A few months ago I wrote this module but, coming back to it, I find it a bit hard to read and reason about. I want to ask community's opinion on whether this needs to be refactored, and how I could ...
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2
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338
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Can this promise be chained more cleanly?
The below code uses Promises/A+ (specifically rsvp.js) to generate a token. It does so by either taking an existing token or downloading and parsing a token from a web page. Is it possible to chain ...
CommunityBot
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jQuery nested ajax deffereds- looking for improvements
Following is a working solution for a single xml ajax to retrieve category list, then individual ajax calls for each category. This was developed in response to a question on SO.
Solution creates one ...
6
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1
answer
5k
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Multiple jQuery promises
I'm starting to reuse this pattern, and was wondering if there was a more succinct/clear way to write it.
Given a function foo taking a callback argument:
...
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1
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362
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Simple jQuery search on input element
Just wanted a way of attaching a jQuery search plugin to an input element (or collection) and be able to pass specific options at invoke time:
This is the plugin code
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