> but many authors choose to show their examples in JS, in order not to be too opinionated

This is certainly true sometimes, but I don't see why it's a reason against using TypeScript? If you're calling a TypeScript API, the way you use it should look basically the same as the way you'd use it in JavaScript. You usually don't have to do anything special with the library's types unless you're getting fancy

There are exceptions- I've had a rough time fighting to get code using the styled-components library to fully typecheck, because that library gets super fancy with the way they represent things (I don't like it for that reason personally, but I know others do). But libraries like that are the exception in my experience, and if it's really that big of a drain on productivity, you can always bail out and use `any` types to skip dealing with it