JAVASCRIPT > les promesses promises

Créer une promise

new Promise((resolve, reject) => {
    maFonction(() => {
        if (success) {
            resolve('good')
        } else {
            reject(new Error('oops'))
        }
    })
})

Consuming promises

promise
    .then((result) => {
        /* success */
    })
    .catch((error) => {
        /* failure */
    })

then() runs a function when a promise resolves. catch() runs when a promise fails.

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) => {
    /* ... */
})

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.