Clean Code

by Robert C. Martin

Why not?

This book is actually quite good, and has a fantastic mindset when implementing its concepts.

The book is very similar to Refactoring, except for these differences:

1. It is older (the second edition of Refactoring is from 2018).
2. It is denser (it spends significantly more time on each refactoring).
3. It has fewer refactorings (but covers the most important).
4. It uses Java for examples rather than JavaScript.

If you know both Java and JavaScript, that last one may not matter, but having to translate the examples while reading causes extra strain. Even without that reason, however, I would still recommend Refactoring.