You should look into TypeScript if you haven't already. It's not perfect, but I think it strikes a nice balance between those two approaches. It's my "go-to" fo

You should look into TypeScript if you haven't already. It's not perfect, but I think it strikes a nice balance between those two approaches. It's my "go-to" for new frontend projects because I enjoy the compiler's flexibility in regards to type checking. I can explore alternate approaches to solving the same problem (and by proxy, tests) and gradually introduce stronger compile-time checks as the solution comes together.