Something like that was my hobby project to learn JavaScript well. (Using the Org::Parser from CPAN.) Far from complete.

I got stuck on that I am unable to create a good UX. :-) You want to give all users a grounding in Emacs and you want to make it usable for others, at the same time.

Now the plan is to get a MVP off the ground and make the View system simple enough so designers can rewrite it and rework the look and command structure.

(This is not just to make a commercial web app based on Emacs, with all income assigned to FSF for fun. Promise. :-) The plan really is GPL.)