I don't feel the posts answer the question, they are more ads to Typescript or Flow. Unsurprisingly the people who answer are the one who use TS or Flow. So I

I don't feel the posts answer the question, they are more ads to Typescript or Flow. Unsurprisingly the people who answer are the one who use TS or Flow. So I tried a little to convert a big React project to Flow or Typescript. The Flow was a non-starter because of the absence of Windows support at the time, and we use like 40 (non dev) dependencies, and Typescript has a way better support for typings, I tried Flow on a mac it was chocking on the size of the node_modules or couldn't find the app modules because we use a webpack root dir (i don't tried hard to make it work). When the app was started Typescript didn't support React so it wasn't written in a "static" way, and accumulated a lot of dynamic idioms, also the backbone of the app is a dynamically generated schema based on XSD and that would be hard to make it compatible with TS type system, also React ecosystem doesn't really use it, leading to a chicken/egg problem, and React.PropTypes is already a form of type checking (but dynamic) so it probably lessen the feeling of a need of static typing in React ecosystem.