Ugh. I have discovered that a library exists for building a UI I have wanted for ~6 years, and I have fallen into a prototyping rabbit hole, fighting a language and a framework I'm unfamiliar with, plus good code with bad documentation. I've never seen anyone spill this many pixels on documentation and fail to mention how it is installed, fail to give a step-by-step hello world, and create dozens of examples none of which can actually be followed successfully without spending hours researching and deducing what it would have taken mere minutes to type out. It's a master class in the curse of expertise.

Is it an open source library? Which one?

So this library has all of the advanced documentation — but not of the basics?

ProseMirror. It has all the reference documentation. No walkthroughs, no how-tos, and the examples are only half specified, so a beginner can't reproduce them. If you are an experienced react dev, I'm sure it's fine. But if ProseMirror is your first reason for wanting to write react code, you are in for a world of hurt. GPT4 saved the day, though.