For example, one project might be to guide your students through writing a simplified version of libraries like React or Angular -- probably after having your students use those libraries directly so they know what they're trying to emulate. This can be an opportunity to teach about some of the more interesting programming paradigms like functional reactive programming. (React was originally written in Ocaml, so you could maybe dovetail things there).
More broadly, I think teaching your students how more complex libraries or framework work is likely to be a more valuable and long-lasting skill compared to just teaching whatever language or library is trendy today. I don't think it particularly matters which library or framework you're implementing: the main value comes from the act of exploring some non-trivial implementation, and from "peeking" under the layers of abstraction we're already used to. And if you can give students exposure to JS (or whatever other language) at the same time, great.