It started off rather ok, because I already went through a React course. However, the next chapters revealed why people dislike this book. It just throws some code at you with rather shallow explanation or even the purpose of usage. It was just boring and felt like very rushed. I surely wouldn't master React after finishing this book. Unfinished at 31%
The material is far enough out of date that it seriously affects the usefulness of the book, however the authors worked very hard on creating a solid tutorial application. The only critique on their teaching style is they built a monolithic application that was not capable of fully running until the 2nd to last chapter, making it a beast to debug (especially considering I was trying to work with a much newer version of React than the version they used in the book). It's quite a project to get everything working, but a great experience nonetheless.
2 stars. I didn't mind the fact information is outdated, I can pretty understand why. However, I expected the author could go deeper in concept explanations, specially about redux. Instead, he started spreading a pile of code with some strange solutions that probably could be better designed, specially if it had automated tests in mind. By the way, he doesn't even mention automated tests. I probably set too high expectations beforehand due to the "Mastering" part of its title.