I mostly agree with you. Just wanted to add that in some languages, for example in Typescript, there are ways to say that you do not care about the type for prototyping. For example using :unknown or :any.
:unknown is great, but the problems come in the middle area; when you have lots of very tight types and are prototyping something that makes use of those things, :unknown doesn't work, and :any can be too expressive, even for your prototype.
This is true. But also I've noticed many less experienced TS devs end up writing types that are too specific and not utilizing structural typing enough. So e.g. writing some type and demanding a function accept it, when that function only actually needs one or two properties from it. Instead that function can inline or localize the part of the type it needs, and the original type can be unaware its ever being used by some other function.
And the other thing is trying to leverage the type system too much. For my style, if the types aren't making things easier to read, write, and maintain, they should be loosened and / or duplicated. I blame a lot of libraries here, it should never be puzzling to figure out how to type something so a function accepts it, yet that comes up quite often; I end up diving through these nested and overly DRY types trying to find what the heck even is this thing? That's crazy. If you need to cmd+click more than once or twice to understand what a type is, its way too abstracted.
Sorry, but that is moving the goalposts. Quick prototyping was mentioned, but now we seem to be talking about some undefined balance between typing and no typing for prototyping. It seems :any solves the problem.
