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.
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Exercise to fetch data from JSON files using ES6 promises
I did an exercise (self-imposed) promise fetching some data from placeholder JSON files on https://jsonplaceholder.typicode.com/. The exercise in my opinion is finished, but I can't shake the feeling ...
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Script to load controllers dynamically for AngularJS
I would like to hear your thoughts, idea's or feedback on the following code.
Ive added to code to github.
https://github.com/redbullzuiper/angularjs-dynamic-controllers
Usually when you attach a ...
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Promise.all, but with enforced limit on concurrent promises
I'm trying to implement parallelLimit() to limit the number of parallel tasks that can be performed at any time. Personally, I'm using this function for limiting ...
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Read files from a directory using Promises
Using javascript functions and the old way of doing things I wrote a piece of code to copy the first file in a directory to a file Test.
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Using await to break long-running processes
I have a Node.js app / Web API that runs on an Azure app service with a single CPU.
One of the functions needs to run for a long time, perhaps tens of seconds, while the server should continue to ...
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Asynchronous Queue
implemented a basic Asynchronous Queue so, that I can do
await queue.push(item);
const item = await queue.pop();
basically I'm trying to convert a synchronous ...
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Fetching user details, posts, and comments using promises in ExpressJS
I'm creating an API service in NodeJS using Express (version 4) Framework. Created an MVC architecture for the same (no views, only model, and controller as this is an API).
Also, there are routes. ...
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Parallel and Sequential array looping with async/await
Are these good implementations of parallel and sequential "extension" methods, and do they accomplish what I think they do?
My understanding is that the first one is parallel because the await ...
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Monkey-patching Jasmine's it() function to log errors
The introduction of async native support in Jasmine doesn't log the errors (i.e., specific line number where the error occurs) to the console. So, to get around this behavior and to make the errors ...
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Asynchronous Stack
implemented a basic asynchronous stack so, that I can do.
await stack.push(item);
const item = await stack.pop();
basically I'm registering listeners when ever i'...
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Blocking Promise-driven queues with ECMAScript's async/await and generators
I implemented an AsyncQueue, whose dequeue() operation returns a Promise. The ...
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Generator function to enumerate files
I want to implement a function that enumerates all files in directory. I think the function should
Return a Promise, because underlying readdir call is prefered ...
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JavaScript / Express error handling w/ promises
So I'm wondering how to properly handle errors in JavaScript when utilizing promises. I'm currently throwing errors for everything so that I can break out of the promise - if I can't find something, ...
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Chaining three promises in Angular.JS
I have demonstrated promise chaining where promise's p1,p2,p3 has to be resolved synchronously.
The code below is using angular.js 1, and here P3 is resolved then P2 and then P1.
...
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Async database helper function in TypeScript
I have made an async function in TypeScript that responds to Events and returns an object with methods that return a promise. I ...
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Calling a promise recursively
I'm trying to call a promise recursively. If I get a responseData with a key error I want to call the promise again and again until I don't get it.
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Exception handling and releasing of OracleDB connection
Before I start implementing several REST API service endpoints, I'd like to make sure that I'm not doing it totally wrong.
...
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TypeScript based Promise/A+ compliant, awaitable promise class for Node.js
This is yet another Node.js Promise implementation, but this is written in TypeScript, and it strives for type safety and clarity. The full project is located here. Feel free to download it and test ...
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Pass Async function to new Promise constructor
I'm having a hard time wrapping my head around whether or not this works or how I can even test it but....
I want to use Async/Await inside a Promise, which means, when I create a new Promise, I ...
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Chaining async functions of a module without Promises
I know that promises are the current recommended way to go for asynchronous chaining but, every time I use promises, I don't feel as comfortable as I wish. All that "then" statements and managing ...
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Translating words from one language to another
My program translates words from one language to another using a language Pivot and systran.io API.
I used promises, callbacks and external API for the first time but I'm not sure that's the best way ...
CommunityBot
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Nested loop with synchronous and asynchronous behavior
The problem is as follows. I have an array of objects like so:
...
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Processing concurrent AJAX requests
I am trying to process concurrent AJAX requests with vanilla JavaScript. Below is the sample code I've been working with
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Showing a Wikipedia article's changes as Git commits
I created a small-ish NodeJS script which takes as argument the name of a Wikipedia article (and optionally a Wikipedia edition, "en" is default) and creates a Git repository with each change made to ...
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Asynchronous JavaScript to fetch remote JSON data with promises and generators
I am trying to figure out how to do async calls using promises and generators (without 3rd party libraries). Most of the examples I found on the Internet are either incomplete or confusing (at least ...
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Fetching AJAX results from three endpoints, with error handling
I have a requirement in which I need to get data by making AJAX calls. First search for data in endPoint1, if not found then in ...
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Iterate array with delay in between using promise
I would like to write a nodejs IP driver for my AVR. In order to turn on my AVR and switch it to channel '321' i have to send key presses. A key press can be seen as a 'press key' and 'release key' ...
CommunityBot
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Session generator/checker utility for a server
I wrote a utility for generating and saving sessions in a MongoDB database as well as checking the session to make sure it's valid.
I'm a beginner when it comes to promises and I have a feeling that ...
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RSVP.hash replacement using ES6 Promise
We have a pretty big code base that made use of RSVP which we are moving to node 4.3.2+. The only RSVP feature we use frequently that's not in the native js Promise api is the hash() function. I ...
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Return a Promise for a JSON POST
Given this method, we don't know which syntax is the more appropriate.
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Javascript progress bar in succession
In the below code snippet, on click of a button, progress bars are added one by one. The bar shows up for 3 seconds. If you continuously click on the button, it will keep adding progress bars. The ...
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Non-polling implementation of std::when_any()
The following — I claim — is a implementation of when_any from the C++ Concurrency TS, except without all the baggage around ...
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Chaining promises into a callback
I wrote a AWS lambda function which buys €X worth of some currency on an exchange. For this I first have to find out the current price (getAskPrice), then calculate ...
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Checking a DB table before doing an insert using AWS Lambda
Pretty new to AWS Lambda and Javascript, and particularly Promises.
Simple check db table before insert.
It all seems to be working - I'm just wondering if there was a neater way of doing any of ...
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code duplication in conditional Promise
I am writing a function in Typescript that involves checking a condition, doing some extra processing if the condition is satisfied, and then doing the bulk of the job.
Here's the catch: the extra ...
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Exporting functions that manipulate mongoose models
I have the following code in a file called database.js which will handle all the database operations for my small application. For some background, this application ...
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Angular 2 service to upload a batch job and poll for results
I have to write a web interface for one of my homebrew projects. Since I'm not familiar with HTML and CSS I've decided to take heavy duty framework such as Angular 2. This is my first experiment - I'm ...
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Fetching data from a MySQL database using Promise
I have written JavaScript code for fetching data from a MySQL database. I have used connection pooling and Promise API.
...
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Fetching and shortening URLs with API calls using Promises
I have a node module that accesses the News API to fetch news articles and runs each article's URL through Google's URL shortener. It also has a caching mechanism implemented. This was previously ...
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Deleting rooms using nested promises
I have a piece of code that has to deal with some nested promises and shared variables between them. This code is complicated by itself and because of promises syntax is even more difficult to read ...
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express-validator and promise chains
Is this the correct way of chaining promises when it comes to express-validator? I am using express node and this is the endpoint for a get request
Something about it seems a bit messy, but I can't ...
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Handling login using promises
We've got this node.js code which is called by an Express route:
...
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1
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Basic web scrape project written in NodeJS
Here is a short program web scraping program written in Node.js. I'm just getting to grips with node and this is the first thing I've written with it. I'm liking it so far though I guess I'm kinda ...
CommunityBot
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Promise-based unit tests using Pub/Sub
I've recently been learning and adopting Promises, async/await, and unit testing for my JavaScript server project. I just finished a unit test for some pubsub code that was more convoluted than ...
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Ensure every element in array passes asynchronous test
I've written a function which ensures all objects in the items array belong to the user. This involves a database check, which ...
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Using JavaScript promises to display weather and location information
This is the first time I'm trying to use promises in JavaScript so I'm not sure if I have done it correctly, but it seems to work. The problem is that I have ended up with a "nested ...
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Parallel class for javascript promises
I created a class to run a certain number of tasks in parallel in the browser. The constructor takes an array of inputs, a function that takes a single input and returns a promise, and a count of the ...
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Simple Promise implementation
I am trying to hack together a simple promise implementation.
Is the following approach of maintaining a single async call and linking nested promises dynamically using their ...
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A function that debits a virtual wallet and calls an API to disburse to a real account
I am trying to determine if there is a better way to handle reversals for this function.
This is how it works:
A user inputs in amount, bank, and account number this would be used to debit his ...
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