Yes, I think that would be just fine as long as the modules encapsulated the "native" functionality of the editor. As long as developers could easily orchestrat

Yes, I think that would be just fine as long as the modules encapsulated the "native" functionality of the editor. As long as developers could easily orchestrate and build on top of existing editor (& built-in git, terminal, extension, etc.) functionality without having to reimplement it from basic JS string processing, JS (incl. but not requiring TS) would seem the logical choice.