As of 2019… …the correct answer is to use async/await with the native fs promises module included in node. Upgrade to Node.js 10 or 11 (already supported by major cloud providers) and do this: const fs = require(‘fs’).promises; // This must run inside a function marked `async`: const file = await fs.readFile(‘filename.txt’, ‘utf8’); await fs.writeFile(‘filename.txt’, … Read more
Axios does not support canceling requests at the moment. Please see this issue for details. UPDATE: Cancellation support was added in axios v0.15. EDIT: The axios cancel token API is based on the withdrawn cancelable promises proposal. UPDATE 2022: Starting from v0.22.0 Axios supports AbortController to cancel requests in fetch API way: Example: const controller … Read more
The current lib.d.ts doesn’t have promises in it defined so you need a extra definition file for it that is why you are getting compilation errors. You could for example use (like @elclanrs says) use the es6-promise package with the definition file from DefinitelyTyped: es6-promise definition You can then use it like this: var p … Read more
You can use Promise.all (spec, MDN) for that: It accepts a bunch of individual promises and gives you back a single promise that is resolved when all of the ones you gave it are resolved, or rejected when any of them is rejected. So if you make doSomeAsyncStuff return a promise, then: const promises = … Read more
JavaScript has the concept of “run to completion”. Unless an error is thrown, a function is executed until a return statement or its end is reached. Other code outside of the function can’t interfere with that (unless, again, an error is thrown). If you want resolve() to exit your initializer function, you have to prepend … Read more
As others have explained, the “black hole” is because throwing inside a .catch continues the chain with a rejected promise, and you have no more catches, leading to an unterminated chain, which swallows errors (bad!) Add one more catch to see what’s happening: do1().then(do2).catch(function(err) { //console.log(err.stack); // This is the only way to see the … Read more
Is there a method for clearing the .thens of a JavaScript Promise instance? No. Not in ECMAScript 6 at least. Promises (and their then handlers) are uncancellable by default (unfortunately). There is a bit of discussion on es-discuss (e.g. here) about how to do this in the right way, but whatever approach will win it … Read more
actions in Vuex are asynchronous. The only way to let the calling function (initiator of action) to know that an action is complete – is by returning a Promise and resolving it later. Here is an example: myAction returns a Promise, makes a http call and resolves or rejects the Promise later – all asynchronously … Read more
Wrap your Promise inside a function or it will start to do its job right away. Plus, you can pass parameters to the function: var some_function = function (username, password) { return new Promise(function (resolve, reject) { /* stuff using username, password */ if (/* everything turned out fine */) { resolve(“Stuff worked!”); } else … Read more
P-Limit I have compared promise concurrency limitation with a custom script, bluebird, es6-promise-pool, and p-limit. I believe that p-limit has the most simple, stripped down implementation for this need. See their documentation. Requirements To be compatible with async in example ECMAScript 2017 (version 8) Node version > 8.2.1 My Example In this example, we need … Read more