Fast prototyping without types? Meh! I need types to be able to prototype and change things really fast, knowing that it won't break. I feel a lot more confide

Fast prototyping without types? Meh! I need types to be able to prototype and change things really fast, knowing that it won't break. I feel a lot more confident to prototype in OCaml/F# and then "downgrade" to an 'ordinary' language that needs more people to understand what is written, than the other way around (prototype in Python and move to something 'real' later) I think that recent movement to put types in dynamic languages is just because of the need to fix existing projects, people are finally "getting it". TypeScript is awesome in this regard. Almost makes JS bearable.