Have you run into an error that goes something like "undefined method 'id' for Nil (compile-time type is (User | Nil))". Understand the error and how to resolve it in this LuckyCast!

As applications grow in complexity, you'll need to store logic in separate files. Let's take a look at the different ways to require files in Crystal in this latest Crystal Mastery mirror!

Get started with Crystal with a short and sweet overview of how to create, run, and build your first program.