[cdaringe]

Probably the OP meant “allowJs” and “noEmit” flags give you limited actual typechecking in your JS files

[tacone]

Exactly. You would use jsconfig in place of tsconfig, and disable the build just like you said. At that point you can use JSDoc for typing as well as .ts.d files when the JSDoc is not enough.

It's a bit more verbose, but overall I find it refreshing.