If you’re looking to get started with React, then the (massive) React Handbook will come in handy.
The React Handbook follows the 80/20 rule: learn in 20% of the time the 80% of a topic.
Best part of it all is that it starts with a big section on Modern JavaScript (e.g. ES2015 and newer) as people seem to confuse ES2015+ with React.
Also available as an ebook in PDF, ePub and Mobi.
The React Handbook (Blogpost) →
The React Handbook (eBook) →