You don't even need to do this much, you can just invoke the function and let th...

You don't even need to do this much, you can just invoke the function and let the return type be inferred.

  const inferred = (() => "Hello")() // Inferred as "string"

If you really don't want to use an IIFE because you don't like the "()" at the end, you can just:

  const myFn = () => { switch(...) }
  const inferred = myFn()