Throw it's a more elegant way to use an exception-like system as a control flow.

Literally, everything in this example can go wrong. Here’s an incomplete list of all possible errors that might occur: Your network might be down, so request won’t happen at all The server might be down The server might be too busy and you will face a timeout The server might require an authentication API endpoint might not exist The user might not exist You might not have enough permissions to view it The server might fail with an internal error while processing your request The server might return an invalid or corrupted response The server might return invalid json, so the parsing will fail And the list goes on and on! There are so maybe potential problems with these three lines of code, that it is easier to say that it only accidentally works. And normally it fails with the exception.

Exceptions are just like notorious goto statements that torn the fabric of our programs.

As you can see, we end up with a lot of boilerplate if-statements. The code is more verbose. And it’s difficult to follow the main logic.

In JavaScript, we have a built-in language feature for dealing with exceptions. We wrap problematic code in a try…catch statement. This lets us write the ‘happy path’ in the try section, and then deal with any exceptions in the catch section. And this is not a bad thing. It allows us to focus on the task at hand, without having to think about every possible error that might occur.

And they are not the only way to handle errors.

In this article, we’ll take a look at using the ‘Either monad’ as an alternative to try...catch.