In modern JavaScript we have several Promise combinators (Promise.all, Promise.race, Promise.allSettled). With the release of ES2021 you also got Promise.any — a lesser-used but powerful tool when you care about the first fulfilled Promise, not the first settled one.

What is Promise.any()

Promise.any(iterable) takes an iterable of Promises and returns a single Promise that fulfills as soon as any of the input promises fulfills. If all of the input promises reject, it returns a promise that rejects with an AggregateError.

Why use it instead of Promise.race()

• Promise.race() settles as soon as any promise settles (resolve or reject).
• Promise.any() resolves as soon as any promise resolves (i.e., fulfils). If one resolves quickly, you don’t wait for the rest.
• Example: pinging multiple servers, you want the first successful response — Promise.any() is ideal.

Example

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const p1 = fetch('/server1').then(resp => resp.json());
const p2 = fetch('/server2').then(resp => resp.json());
const p3 = fetch('/server3').then(resp => resp.json());

Promise.any([p1, p2, p3])
  .then(result => {
    console.log('First successful result:', result);
  })
  .catch(error => {
    console.error('All failed:', error);
  });

Caveats

• If all promises reject, you get an AggregateError with .errors property.

• Not supported in older browsers without polyfill.

• Doesn’t cancel the other promises — they still run (you could build cancellation logic yourself).

• Monitoring or debugging can be trickier if many promises live on.

When to use

• Multiple APIs/mirrors and you want the first success.

• Redundant service endpoints.

• Race-to-fulfill scenarios rather than race to settle (which may reject).

Summary

Promise.any() is a succinct way to get the first successful result out of many asynchronous operations, improving performance in the right scenarios. It’s part of your JavaScript toolbox for modern asynchronous workflows.