[bcherny]

I have used Flow for a few projects.

I think we're saying the same thing. By "linter" I mean a program that only checks for stylistic and defined/undefined errors. To me, anything beyond that is a typechecker. Whereas TS bundles a typechecker with a transpiler, Flow keeps the 2 separate (you still need both if your program is written using Flow syntax).

You are using "linter" more broadly, which may be fair as well.

Additionally, both TS and Flow can be used on JS files with zero modification.