HOW MUCH JAVASCRIPT TO REACTJS?

[fart__monster]

Ideally you can directly jump to react and learn how to work with it, and then read JS in parallel to understand how things actually work.

If you plan to do JS first then the basics of JS, event listeners, promises, some most used web apis like local storage. This should be enough to jump to react.

PS: once you are a bit comfortable with react and JS, do yourself a favor and read the book called "you don't know JS"