I find that most of the pain/complexity around TypeScript types happens when you're trying to write super dynamic or polymorphic JavaScript-style code and then

I find that most of the pain/complexity around TypeScript types happens when you're trying to write super dynamic or polymorphic JavaScript-style code and then put types on top. This comes out especially when adding types to an existing codebase. I can definitely see how this would affect library authors more than application authors, but I'm not sure it's TypeScript's fault, and I think it can be avoided by making different choices about what interfaces you expose Or, worst-case, just weakening your types. Plenty of libraries have weaker types than they could have, but sometimes it's justified because it would be hard to get them exactly right