I used to make the same argument, about not using TS for prototyping, but the tooling is so good that at this point, I generally just change the file extension

I used to make the same argument, about not using TS for prototyping, but the tooling is so good that at this point, I generally just change the file extension to ".ts" and write no manual types for the mistakes and type-hints + intellisense the compiler and language server provide.