Book was not entertaining. Absolute slog to get through. But eh, got Typescript fundamentals down. But really, the fact that the types system is so complex is kind of amazing. I don't know whether I'll be using them with DefinitelyTypes. And having Types being strings like "Animal" will get me some to get used to, but I can see the power with them.
This book is not a quick read. Grinded a few pages a day just to give myself some time to digest the concepts.