[zimmerx]

This does not solve the problem of bad documentation or bad libraries. Points to make his case are weak. Better autocomplete? Reliable libraries? The library still compiles to JS and you can still use TypeScript naively and incorrectly and ignore typesetting altogether.

TypeScript doesn't solve the problem at all. It merely adds another layer of complexity/knowledge to a Library that still compiles to JavaScript. Write it in JavaScript, deliver it in JavaScript. If your documentation and implicit typesetting is giving you pains, then you should revisit what you have written and how you've built your library. Not switch to something that tries to enforce better behaviour.