Breaking change with TypeScript: migrating from Deno to Bun

Hey everyone,

We recently launched our Typescript Track (TypeScript track is live!), and found during beta testing that a lot of Deno behaviour was confusing, especially things like deno.lock and deno.json.

We’re instead migrating to Bun. If you’ve already created a TypeScript repository you should soon see an email that points to this post.

Upgrade instructions

When you run tests / git push on your old typescript repository, you’ll now see this error message:

If you aren’t far along in the challenge, deleting your current repository and creating a new one is a simple way to fix everything. You’ll find the delete button here:

If you do want to retain progress on the current repository:

  1. Change the value of language_pack in your codecrafters.yml from deno-1.42 to bun-1.1:

  1. Run bun install locally so that you get the following files created:

You can use the default options for package name, entry point etc.

  1. Finally, change

That should be it! Tests should run fine on your next git push.

Please let us know here if you run into any issues.