Performing safe, pure refactorings is a skill that can make a big difference on your code maintainability. Hopefully, IDE like Jetbrains have automated a lot of them, in many languages. But what if your text editor doesn't provide automated refactorings for your language? Consider VS Code: it is increasingly popular, yet it misses most refactorings for JavaScript. However, you can customize VS Code through extensions. Have you ever thought about creating your own? In this session, I will show you how to build an extension that refactors JavaScript code for you! You'll learn how to manipulate the Abstract Syntax Tree (AST). Together, we will create, configure, package and publish your first VS Code Extension.