Promise.allSettled in babel ES6 implementation

Question

I'm using babel to transpile my [email protected] code and I'm stuck with promises.

I need allSettled-type functionality that I could use in q and bluebird or angular.$q for example.

On babel's core-js Promise, there is no allSettled method.

Currently I'm using q.allSettled as a workaround:

import { allSettled } from 'q';

Is there something like that in babel polyfill? Alternatively, which is a good algorithm for me to try to implement?

Answer 1

2019 Answer

There was a proposal to add this function to the ECMAScript standard, and it has been accepted! Check out the Promise.allSettled docs for details.

Original Answer

If you take a look at the implementation of q.allSettled you'll see it's actually quite simple to implement. Here's how you might implement it using ES6 Promises:

function allSettled(promises) {
    let wrappedPromises = promises.map(p => Promise.resolve(p)
        .then(
            val => ({ status: 'fulfilled', value: val }),
            err => ({ status: 'rejected', reason: err })));
    return Promise.all(wrappedPromises);
}