Homelab, Linux, JS & ABAP (~˘▾˘)~

[JavaScript] Working with Promises in 2024

Since ES2024 there is a new way to create promises by using the withResolver function:

// ES 6 Via Constructor
const promise = new Promise((resolve, reject) => { }

// ES2024 Via factory function
const [promise, resolve, reject] = Promise.withResolver( )

Since ES2018 there is an additional handler called finally:

const promise = fetch("/myAPI")

  .then(response => console.log(response))
  .catch(error => console.error(error))
  .finally(() => console.log("Called in any case"))

And handling multiple Promises has been made easier by the new methods allSettled, any, race which were introduced in ES2020 and ES2015:

// Promise that resolves when all promises are resolved
const promise = Promise.all([promiseA, promiseB])
promise.then(([valueA, valueB]) => console.log(valueA, valueB))

// ES2020 Promise that resolves when all promises are settled (either resolved or rejected)
const promise = Promise.allSettled([promiseA, promiseB])

// ES2020 Promise that resolves when either promiseA or promiseB is resolved
const promise = Promise.any([promiseA, promiseB])

// ES2015 Promise that resolves/rejects when any promise is resolved or rejected
const promise = Promise.race([promiseA, promiseB])

Leave a Reply

Your email address will not be published. Required fields are marked *