Promise.allSettled()

iterable

An iterable object, such as an Array, in which each member is a Promise.

A pending Promise that will be asynchronously fulfilled once every promise in the specified collection of promises has completed, either by successfully being fulfilled or by being rejected. At that time, the returned promise's handler is passed as input an array containing the outcome of each promise in the original set of promises.

However, if and only if an empty iterable is passed as an argument, Promise.allSettled() returns a Promise object that has already been resolved as an empty array.

For each outcome object, a status string is present. If the status is fulfilled, then a value is present. If the status is rejected, then a reason is present. The value (or reason) reflects what value each promise was fulfilled (or rejected) with.

Promise.prototype.then()

Promise.allSettled([
  Promise.resolve(33),
  new Promise(resolve => setTimeout(() => resolve(66), 0)),
  99,
  Promise.reject(new Error('an error'))
])
.then(values => console.log(values));

// [
//   {status: "fulfilled", value: 33},
//   {status: "fulfilled", value: 66},
//   {status: "fulfilled", value: 99},
//   {status: "rejected",  reason: Error: an error}
// ]

await

const values = await Promise.allSettled([
  Promise.resolve(33),
  new Promise(resolve => setTimeout(() => resolve(66), 0)),
  99,
  Promise.reject(new Error('an error'))
])
console.log(values)

// [
//   {status: "fulfilled", value: 33},
//   {status: "fulfilled", value: 66},
//   {status: "fulfilled", value: 99},
//   {status: "rejected",  reason: Error: an error}
// ]

• Polyfill of Promise.allSettled in core-js
• Promises
• Using promises
• Graceful asynchronous programming with promises
• Promise
• Promise.all()