There are lots of docs, and in most cases the quality at some point was good, but they're often out of date, and old versions hang around for a long time. Real world projects often use wildly different versions of React (because it's hard to keep up with the version churn) so I guess all those different doc versions are necessary.
For React Native, the docs are missing detail so you have to look at the code, and the code comments were pretty spotty and inconsistent the last time I looked.
Comments
React, especially React Native.
There are lots of docs, and in most cases the quality at some point was good, but they're often out of date, and old versions hang around for a long time. Real world projects often use wildly different versions of React (because it's hard to keep up with the version churn) so I guess all those different doc versions are necessary.
For React Native, the docs are missing detail so you have to look at the code, and the code comments were pretty spotty and inconsistent the last time I looked.