Beforehand I built something very similar to what you described for Flow (https://hackernoon.com/runtime-introspection-of-flow-types-d...).

Many others superseded this implementation, the above being one example.

There's also very similar project at https://github.com/pelotom/runtypes that our company uses. Don't have enough experience with it yet to say which is better, io-ts on runtypes.