I still use CS for prototyping. It's easy to write and what's most important it's easy to read due to lack of visual clutter of JS. Once I have something decent

I still use CS for prototyping. It's easy to write and what's most important it's easy to read due to lack of visual clutter of JS. Once I have something decent I just take JS output and annotate it with types and work on it further debugging and optimizing.