This is satire right? Right?
No, this is just some guy who cannot solve trivial problems without Intellij holding his hand, and he feels like that entitles him to an opinion
The trivial problem here being knowing what kinda of parameter some random function somewhere in your code expects… And your code not randomly breaking in production when someone changes that function after you already used it, unless you wrote unit tests that literally test every single line of code.
Tests are supposed to ensure functionality, not implementation. No useful unit test has ever been made obsolete by a type system. Likewise, if your tests claim your program fulfills its functionality, the type system ads no additional information to the discussion.
My sense is that this argument primarily holds for teams without thorough code reviews. For individuals or teams with good reviews, TypeScript adds little except for complex code or massive rewrites. I’m not saying it adds little in absolute terms, but that it adds little once you account for the overhead of using it.