Now I'll teach you how to handle a rejected Promise.

If an error occurs, the Promise status changes from pending to a rejected, or

failed state.

The good thing is that promises give you the opportunity to handle the error with

a method called catch.

I'll start by changing resolve to reject.

And pass it the string, No!

There was a problem with your order.

Now I can call the catch method on breakfastPromise,

which deals with rejected cases only.

I can do that by chaining it to the then method, like so.

The function passed to catch takes one argument, which is the rejection reason,

or the error message to display.

I'll pass catch an arrow function that takes the parameter, err, and

logs it to the console.

I'll Save my file and run it in the terminal.

The reject method changes the status of the Promise from pending to rejected.

So this time, instead of then, catch gets called,

invoking the function passed to it and in the Console we see the message, No!

There was a problem with your order.

Keep in mind that if you don't specify reject and

a catch method to handle a rejected Promise, the Promise will fail silently.

Errors will be swallowed up with no side effects to the rest of your app.

In other words, the program will continue to execute as if everything was fine.

Now that you know how resolve and reject work, I'm going to write a conditional

statement inside setTimeout that checks the true and false value of an order.

Let's have it say if order is true resolve

this promise to the value Your order is ready.

Come and get it!

Else, if it's false, reject the Promise and

set the rejection reason to Your order cannot be made.

This time I'm passing the Error object to reject versus only a string.

While it's not required, it does help with debugging because it will display

the stack trace alongside the rejection reason.

All right, so now to test this,

I'll initialize a variable named order to true.

I'll run the file in the Console, since order is true,

the Promise resolves to Your order is ready.

Come and get it.

Now, I'll change order to false and run the file again.

This time the Promise is rejected, so the rejection reason,

Your order cannot be made, displays in the Console, followed by the stat trace.

Good, finally to make your code more readable and

the Promise sequence easier to follow, you can place each then and

catch call on a separate line like this.

This approach will come in handy starting in the next step,

where you'll chain together a sequence of Promises.