I would suggest just one aspect, whether designing (find an offline tool), building (take offline React reference docs), or something else and go deep into that

I would suggest just one aspect, whether designing (find an offline tool), building (take offline React reference docs), or something else and go deep into that. Typically I take a toy project and build it with a different language/style and framework (or without a framework). If I were in a circumstance like that I might take Ruby & Rails docs. I use it, but don't know to the point of memorization so many things that are uncommon but frequent enough that I have to take time to look them up each time they come up. Like how does Ruby symbol resolution work, exactly.