Information about Promise

https://javascript.info/promise-basics

const f = (resolve, error) => {
   if ( 2 > 1 ) {
      resolve(12345)
   }
}

const p = new Promise(f)

const dofinalstuff = () => console.log('Do final stuff')

const dosomething = (result) => console.log('Hello ' + result)

const doerror = (error) => console.log('error: ' + error)

p.finally(dofinalstuff).then(dosomething, doerror)

function delay(ms) {
  return new Promise(resolve => setTimeout(resolve, ms));
}

delay(3000).then(() => alert('runs after 3 seconds'));

new Promise((resolve, reject) => {
  throw new Error("error");
})
  .finally(() => alert("Promise ready")) // triggers first
  .catch(err => alert(err));  // <-- .catch shows the error

 Promise.race()

Promise.race() is used to handle multiple concurrent promises.

Promise.race() waits for only one promise to resolve or reject.

Promise.race([promise1, promise2, promise3])
   .then(results => console.log(results))
   .catch(error => console.log(error))

Promise.all()

Promise.all() waits until all the promises have completed.

// Promise.all) method is used to handle multiple promises concurrently.
const promisel = new Promise((resolve) => setTimeout(resolve, 1000, "Hello"));
const promise = new Promise ((resolve) => setTimeout(resolve, 2000, "World"));
const promise = new Promise((resolve) => setTimeout (resolve, 1500, "Happy"));
//


// Promise.all takes an array of promises as input and returns a new promise.
Promise.all([promise1, promise, promise31)
    .then ((results) => {
         console.log(results)
})

    .catch ((error) => {
         console. error ("Error:", error);
｝）；


// Output: ['Hello', 'World", "Happy']