[Reference] Converting other promises
return Promise.resolve('result')
return Promise.resolve(promise)
return Promise.resolve(thenable)
return Promise.reject('reason')
Promise.resolve(result).then(() => {
/* ... */
})
Promise.resolve(val) will return a promise that resolves to the value given to it.
[Reference] Multiple promises
const promises = [promise1(), promise2() /* ... */]
// Succeeds when all succeed
Promise.all(promises).then((results) => {
/* ... */
})
// Succeeds when one finishes first
Promise.race(promises).then((result) => {
/* ... */
})
[Reference] Consuming promises
promise
.then((result) => {
/* success */
})
.catch((error) => {
/* failure */
})
then() runs a function when a promise resolves. catch() runs when a promise fails.
[Reference] Creating promises
new Promise((resolve, reject) => {
doStuff(() => {
if (success) {
resolve('good')
} else {
reject(new Error('oops'))
}
})
})
Use new Promise to create new promises.
[Reference] Introduction
Intro: A quick reference to the JavaScript Promise API.
- Using Promises guide (developer.mozilla.org)
- Promise documentation (developer.mozilla.org)
- Promises Cheat Sheet - Cheat Sheet Maker
Top comments (0)