I prefer starting from theory and then proceed with practicing. For example, to learn haskell and deeply understand it, I started by taking a course in category theory and I already have a degree in computer science and then start writing actual code. The same with JS. I started with theory for JIT compilers and studied how V8 works, how it utilizes event loops and how they are implemented in the kernel. Then I started experimenting with code and demos. It's a success path for me, that has worked every time with every new technology.