> One of the worries we had with Flow was that it was built to solve specific needs at Facebook and that its future would be determined by that scope.
if you replace [Flow/Facebook] with [Dart/Google] , I guess you could make the same point.
Microsoft saved them from themselves. (I expect they could have arranged to have the feature added without first publicly declaring their intention to fork the language, but that's above their community engagement skill level.)
Google's Closure Compiler was the best version of compiled JavaScript for five years. It should have been the winner, but Google did nothing to make it palatable to the open-source community (docs are a disaster, the code is full of unexplained Google-specific workarounds, it integrates with nothing), got trampled, and now they're forced to adopt someone else's tech to remain relevant. Google is so bad at this.
Because Dart is a different language. Typescript is (mostly) Javascript with type annotations, so there is nothing new to learn. In theory, you can just change the extension of a file from .js to .ts to convert it to Typescript.