Because in application you're on consumer side, you have concrete types you're working with, in library on the other hand you're often providing generic code wi

Because in application you're on consumer side, you have concrete types you're working with, in library on the other hand you're often providing generic code with parametric polymorphism, some constraints, you'll use type mapping etc. Before judging it as "terrible" it would be good if author has more constructive criticism - if typescript is "terrible" what is not "terrible", haskell? What are specific things that can be changed to make it simpler? What if typescript is actually very good but the underlying type theory is just inherently complex? You also have to appreciate what kind of value it brings to library users - and imho, in many cases, the value is so high that the whole discussion is a nobrainer. In my opinion - if you want to use typescript, you need to learn it, especially when writing libraries. It doesn't make sense to want to use something and not want to learn it at the same time.