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Promise.any

Promise.any

Introduction

Promise.any resolves with the first fulfilled promise. It rejects only if all promises reject (with an AggregateError).

Basic Usage

const promises = [
  fetch('/api/server1').then(r => r.json()),
  fetch('/api/server2').then(r => r.json()),
  fetch('/api/server3').then(r => r.json())
];

Promise.any(promises)
  .then(result => console.log('Got data from fastest server:', result))
  .catch(err => {
    // AggregateError — all promises rejected
    console.error('All servers failed:', err.errors);
  });

Comparison with Promise.race

// Promise.race — first to SETTLE (could be rejection)
Promise.race([
  fetch('/api/data'),
  Promise.reject('Error')
]).then(console.log) // Never runs — rejects immediately

// Promise.any — first to FULFILL (ignores rejections)
Promise.any([
  fetch('/api/data'),
  Promise.reject('Error')
]).then(console.log) // Runs if fetch succeeds

Summary

Resolves with the first fulfilled promise
Rejects with AggregateError only if ALL reject
Unlike Promise.race which rejects on first rejection
Great for redundant/failover scenarios

Further Reading

MDN: Promise.any