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Promise.all(), Promise.race(), Promise.allSettled()

Promise.all( iterable ) returns a Promise with an array of the resolved values after all the promises in the iterable argument have been resolved. Promise.race(iterable) returns a Promise with the resolved value, immediately after the first promise has been resolved or rejected.

Promise.all Settled ( iterable ) returns a Promise with an array of the resolved values after all the promises in the iterable argument have been resolved or rejected.

Notice the asynchrony / parallelism.
RESETRUNFULL
<!DOCTYPE html><html><body><script>

var p1 = new Promise(resolve=>{setTimeout(resolve,400,'1');});var p2 = new Promise(resolve=>{setTimeout(resolve,500,'2');});var p3 = new Promise(resolve=>{setTimeout(resolve,600,'3');});Promise.all([p1,p2,p3]).then(  // the iterable argument can be any iterable, not just array
   a => {for (v of a) console.log(v);});console.log('START');// START, 1, 2, 3
   (after 6 seconds)

</script></body><html>

<!DOCTYPE html><html><body><script>

var p1 = new Promise(resolve=>{setTimeout(resolve,400,'1');});var p2 = new Promise(resolve=>{setTimeout(resolve,500,'2');});var p3 = new Promise(resolve=>{setTimeout(resolve,600,'3');});Promise.race([p1,p2,p3]).then(  // the iterable argument can be any iterable, not just array
   a => {for (v of a) console.log(v);});console.log('START');// START, 1
    (after 4 seconds)

</script></body><html>

<!DOCTYPE html><html><body><script>

(new Promise((resolve,reject)=>{
   console.log(1);
   resolve();})).then(
   ()=>{console.log(2);});console.log('START');// 1, START, 2

</script></body><html>

As soon as any Promise in the iterable argument rejects, Promise.all() or Promise.race() returns a rejected Promise immediately.


RESETRUNFULL
<!DOCTYPE html><html><body><script>

(new Promise((resolve,reject)=>{
   console.log(1);
   resolve();})).then(
   ()=>{console.log(2);});console.log('START');// 1, START, 2

</script></body><html>

<!DOCTYPE html><html><body><script>

var p1 = new Promise((resolve,reject)=>{
   setTimeout(reject,500,'1');});var p2 = new Promise((resolve,reject)=>{
   setTimeout(resolve,100,'2');});var p3 = new Promise((resolve,reject)=>{
   setTimeout(resolve,1000,'3');});Promise.all([p1,p2,p3]).then(
   a => {for (v of a) console.log('(all)'+v);},
   e => {console.log('rejected(all):'+e);});Promise.race([p1,p2,p3]).then(
   a => {for (v of a) console.log('(race)'+v);},
   e => {console.log('rejected(race):'+e);});Promise.allSettled([p1,p2,p3]).then(
   a => {for (v of a) console.log('(allSettled)'+JSON.stringify(v));},);console.log('START');// START, // (race)2,// rejected(all):1// (allSettled){"status":"rejected","reason":"1"}// (allSettled){"status":"fulfilled","reason":"2"}// (allSettled){"status":"fulfilled","reason":"3"}

</script></body><html>

If the iterable argument contains non-promise values, the values are simply passed on to the array for the successCallback in then(). (If the iterable argument is empty, the promise resolves immediately and synchronously.)


RESETRUNFULL
<!DOCTYPE html><html><body><script>

var p1 = Promise.resolve(300);var p2 = 100;var p3 = new Promise((resolve, reject) => {
  setTimeout(resolve, 100, 'hi');}); Promise.all([p1, p2, p3]).then(console.log);                                                             // [300, 100, "hi"] 

</script></body><html>

Do remember that when resolved, Promise.all() returns an array of values while Promise.race() returns a single value.

Promise.any(iterable), added in ECMAScript 2021, returns a Promise that fulfills as soon as any promise in the iterable argument fulfills. If every promise in the iterable rejects (or the iterable is empty), the returned promise rejects with an AggregateError – a new Error subtype whose .errors property is an array of all the individual rejection reasons, in the same order as the iterable.

Promise.any() is the 'opposite' of Promise.all(): it settles on the first success rather than waiting for every promise, and ignores rejections as long as one promise fulfills.
var p1 = new Promise((resolve, reject) => {
  setTimeout(reject, 300, 'p1 failed');
});
var p2 = new Promise((resolve, reject) => {
  setTimeout(resolve, 500, 'p2 won');
});
var p3 = new Promise((resolve, reject) => {
  setTimeout(resolve, 700, 'p3 too slow');
});

Promise.any([p1, p2, p3]).then(v => console.log(v));

'p2 won' (after 500ms; the earlier rejection from p1 is simply ignored)
If every promise rejects, Promise.any() rejects with an AggregateError collecting every reason.
Promise.any([Promise.reject('x'), Promise.reject('y')]).catch(e => {
  console.log(e instanceof AggregateError);
  console.log(e.errors);
});

true ['x', 'y']