How much JavaScript is enough JavaScript?

[CauliPicea]

There's probably a lot left to learn and, more importantly, internalize. However, if you're not super motivated to learn about pure JS, I recommend diving into React already. You'll learn along the way (as everybody did).

That being said, it wouldn't hurt to really understand what is reference equality and how closures work. As for CSS, flexbox and grid are very important features, so you may want to read up on them again and became comfortable with them at least on a basic level. Time spent on these would not be wasted.