- Async/await
- Promises
Just like we can chain array functions like this:
const fastCarBrands = cars
.filter(car => car.speed > 60)
.map(car => car.brand);We can chain promise function aswell, and it works exactly like with chaining array methods or chaining anything in js. We use the return of calling the previous function:
doesBenjaminEndWithN = "BENJAMIN"
.toLowerCase() // <-- toLowerCase returns a string!
.endsWith('n'); // <-- That string we can call .endsWith on!When we deal with promises the chaining part comes because calling the .then function returns a promises!
We know that when we have a promise, we can call .then on that promise
fetch('http://api.open-notify.org/astros.json')
.then(function(response) { // <-- .then returns a promise!
// The returned promise (from calling .then) resolves when response.json() resolves!
return response.json();
})
.then(function(astronautData) { // because the previous .then function returns a promise, we can call .then on that!
});