"This seems to serve dual purposes. 1. Tips on how to minify code, and 2. A list of prohibited code styles for your team."
In golf you want to have the fewest points possible. In code golf you want to write the shortest function possible, just for fun. If you're already comfortable with TDD, then code golf can be a fun way to push your understanding of JS.
Go back to some of your favorite exercises in this chapter and try refactoring your solutions to be as short as humanly possible. Don't forget to run your tests every time you make a change!
PS. Almost everything you'll write in code golf is a bad practice that will not pass linter checks or code review.