Promise finally

Sometimes you may need to avoid duplicate code in the then() and catch() methods.

myPromise
.then(result => {
// process the result and then clean up the resources
})
.catch(error => {
// handle the error and then clean up the resources
});

The finally() method is useful if you want to do some processing or resource cleanup once the promise is settled(i.e either fulfilled or rejected).

Let's take a below example to hide the loading spinner after the data is fetched and processed.

let isLoading = true;
fetch('http://somesite.com/users')
.then(data => data.json())
.catch(err => console.error(err))
.finally(() => {
isLoading = false;
console.log('Finished loading!!');
})

ES2019 Or ES10