I'd bet Flow is basically being replaced by ReasonML at Facebook[1]. Bolting a sound typesystem onto Javascript is really hard, and Flow is making a truly valia

I'd bet Flow is basically being replaced by ReasonML at Facebook[1]. Bolting a sound typesystem onto Javascript is really hard, and Flow is making a truly valiant effort, but it seems to have stalled out. Instead, ReasonML is based on starting from a "cleaned up" semantics and type system, then translating it into raw Javascript. This avoids all the weird edge cases and type inference problems one runs into when trying to use Flow[2]. (I don't ever have to have any `any` in my ReasonML code, but it was unavoidable with Flow.) 1. https://reasonml.github.io/blog/2017/09/08/messenger-50-reason https://reasonml.github.io/blog/2017/09/08/messenger-50-reas... 2. https://github.com/facebook/flow/issues?utf8=&q=is%3Aissue+is%3Aopen+%24ObjMap https://github.com/facebook/flow/issues?utf8=&q=is%3Aissue+i...