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How to work with error handling in Javascript

terrythreatt profile image Terry Threatt ・2 min read

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
  }

}
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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)
  }

}
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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}`)
  }

}
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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."
  }

}
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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

Discussion (4)

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schleidens profile image
Schleidens_DEV

Good article 🚀

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Anvin

Simple and nice

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