So now I want to teach you a third method that's a newer addition to Promises.

It's called finally.

And it gets called once a promise is fully settled.

Meaning, regardless of whether the promise is fulfilled or rejected,

the callback function passed to it gets executed.

Because of this, it's usually best to use finally as the last chain method.

And finally is useful if and

when you need to do some clean up after the promise sequence finished.

For example, when the button is clicked, I want to change the button's text to

loading, then remove the button from the page once all the data is returned.

So first in the EventListener I'll set the text content

of the button on click with event.target.textContent = Loading.

Then chain the finally method to the end of the Promise sequence.

Finally takes a function that's called when the promise is settled.

So next I'll pass the code that removes the button from the page,

event.target.remove into the finally method using an arrow function.

In the browser, click the button and see the text change to Loading.

Then it's removed from the page when the data loads.

The finally method removes the button from the page after the data is fetched and

processed, regardless of whether or not that operation succeeded.

Because of that, if an error occurs, for example,

users may see a blank section of content like this.

So we can use catch to display a user-friendly message to let them

know something went wrong.

For instance, in the catch method, I'll open up a set of curly braces,

since we're going to pass it multiple lines of code.

Then I'll set the innerHTML of the main peopleList div,

To display an h3 with the text, something went wrong.

So now this message is going to appear on the page in the event of an error,

like a connectivity issue or a rejected promise.

So as you've learned so far, promises offer a more intuitive flow.

Whereas callback nesting requires you to jump around to comprehend the code's flow,

promises let you chain then methods to achieve sequential tasks,

providing a more linear reading experience.

Be sure to review the teacher's notes with this video to see more examples of how to

run multiple promises in parallel with promise.all