See the docs repo PR [0] for background on what content is currently included, plans for further content and site improvements, and feedback on the new docs.
For why this is a big deal: the old docs were good in some ways, but very weak in others.
By far the biggest issue is that hooks were announced in Oct 2018 and released live in early 2019, but the tutorials and explanations were all still written with class components and showed older patterns, well after the community had fully adopted hooks as the standard approach. The hooks info was a totally separate section of the docs. That section was _good_, but it made it really hard to continue recommending the React docs as a good starting point for someone new to React.
The docs have also skimmed past a lot of important information, usage concepts, and info on how React itself actually works. For example:
- React's batching behavior is something that frequently trips people up, but the current docs just have a note that says "updates may be async"
- Using the hook dependency arrays correctly is vital, but the current hook docs describe it as sort of an after-thought
- There's no information on what a "reducer function" is or how to use one correctly.
That's part of why I ended up writing a 9K-word "Guide to React Rendering Behavior" post [1], and Dan wrote a similar "Guide to `useEffect`" [2] article.
Fortunately, the new docs address a lot of those concepts directly, which should really help people who are getting started.
[0] https://github.com/reactjs/reactjs.org/pull/3965
[1] https://blog.isquaredsoftware.com/2020/05/blogged-answers-a-...