from what I heard, they use typescript instead of reason for some time already. I don't know if they use react or not. I also heard that they weren't always using reasonreact even when they were using reason. So they've never been 100% on the same stack than what was advertised by the reason team.
It probably explain why fb dedicates so little resources to reason too.
Is that true for ReScript, or no?
Presumably Facebook still uses React? But they use it via regular JS and not Reason or Rescript?
I do have to concur with some of the comments -- the situation seems pretty confusing, and spending a bunch of time looking at docs didn't enlighten me.