In order to encourage people to support my work, I've decided to publish a TL;DR version of this chapter for the community. This will allow me to develop more content, so it's a win-win really.
You can access the full chapter by buying a copy through Leanpub. It goes into detail, whereas the following should give you a rough idea of the chapter contents.
propTypesgive you nice little errors during development, but will be stripped from the production build to improve performance.
flowitself is a static checker you have to run separately, babel-plugin-typecheck provides runtime checks during development.
Buy the book for the rest.