How to work with error handling in Javascript

In programming unintended side-effects called errors can and will happen in your code. Allowing these errors to be introduced to people that are using your programs is frowned upon and a very bad user experience.

Error Handling is the technique of smoothly handling these errors and providing useful information to a user.

Here are the important parts of error handling:

Try

The try block allows you to try an initial blog of code.

async function doWork() {

  try {
    let response = await fetch("www.worktobedone.com") 

    let work = await response.json()

    return work
  }

}

Catch

The catch block allows you to catch an error from the initial blog of code.

async function doWork() {

  try {
    let response = await fetch("www.worktobedone.com") 

    let work = await response.json()

    return work
  } catch(error) {
     // Here we caught an error to alert
     alert(error)
  }

}

Throw

The throw keyword allows you to control or create custom exceptions from your code.

async function doWork() {

  try {
    let response = await fetch("www.worktobedone.com") 

    let work = await response.json()

    return work
  } catch(error) {
     // Lets change the error output
     throw new Error(`Oops we found this error during work - ${error}`)
  }

}

Finally

The finally block allows you to execute code regardless of errors in the try and catch blocks.

async function doWork() {

  try {
    let response = await fetch("www.worktobedone.com") 

    let work = await response.json()

    return work
  } catch(error) {
     throw new Error(`Oops we found this error during work - ${error}`)
  } finally {
   return "My work here is done."
  }

}

Let's chat about error handling

This walkthrough showed the steps to using the try..catch...finally block to handle errors. If you enjoyed this post feel free to leave a comment about your thoughts and experiences handling errors in your code.

Happy Coding,
Terry Threatt