TypScript is sort of this. It's the best of both worlds, if it wasn't built on top of JS legacy garbage type system and core types it would be ideal.
But a powerful structural type system built on a flexible object model is really a great mix - type as much as you need, ignore types when they get in the way.
But a powerful structural type system built on a flexible object model is really a great mix - type as much as you need, ignore types when they get in the way.