// rejected if any of the input Promises are rejected,
// otherwise, fulfilled with an array of values of each Promise.
Promise.all(
// array of URLs -> array of Promises
urls.map(url => fetch(url).then(response => response.text())
).then(
texts => handle(texts) // do something with array of strings
)
replit：
// custom Promise
const promiseFoo = new Promise((resolve, reject) => {
setTimeout(resolve, 2000, 'foo');
// ╰───╯ <---- parameter to `resolve`
});
// ⭐ Promise.all()
// - rejected if any is rejected
// - fulfilled (with array of values) if all are fulfilled
Promise.all([
Promise.resolve(3),
42, // non-Promise value is OK
promiseFoo
]).then(values => {
console.log(values); // [ 3, 42, 'foo' ]
});
// ⭐ Promise.allSettled()
// - always fulfilled with array of outcomes (objects)
Promise.allSettled([
Promise.resolve(1),
Promise.reject('bad boy'),
3,
]).then(results => {
results.forEach(result => console.log(result));
// { status: 'fulfilled', value: 1 } // ⭐ with `value`
// { status: 'rejected' , reason: 'bad boy' } // ⭐ with `reason`
// { status: 'fulfilled', value: 3 }
});
// ⭐ Promise.race()
// - settled immediately if any is settled.
Promise.race([
new Promise(resolve => setTimeout(resolve, 500, 'one')),
new Promise(resolve => setTimeout(resolve, 200, 'two')), // resolve faster
]).then(value => {
console.log(value); // 'two'
});