I am currently using Promise.allSettled
to wait for all my promises to finish(irrespective of whether they resolve or get rejected).
Since my project is compliant to Node v12.3.1
I am unable to use this?
What other simple alternatives can I use.
Sample code:
async function runner() { let promises = []; for(let i=0; i<10; i++) { promises.push(fetcher()) } await Promise.allSettled(promises).then(([results]) => console.log(results.length)); console.log('continue work...'); }
Note:
Promise.allSettled is available from Node version >12.9
.
Adding shims is also not an option.
Advertisement
Answer
There’s a small polyfill trick that you can do manually to simulate the effects of Promise.allSettled
.
Here’s the snippet.
if (!Promise.allSettled) { Promise.allSettled = promises => Promise.all( promises.map((promise, i) => promise .then(value => ({ status: "fulfilled", value, })) .catch(reason => ({ status: "rejected", reason, })) ) ); } Promise.allSettled(promises).then(console.log);
That means map all of the promises, then return the results, either successful or rejected.
An alternative, if you do not want the object-like nature of Promise.all
, the following snippet may help. This is very simple, you just need to add .catch
method here.
const promises = [ fetch('/something'), fetch('/something'), fetch('/something'), ].map(p => p.catch(e => e)); // this will prevent the promise from breaking out, but there will be no 'result-object', unlike the first solution. await Promise.all(promises);