Facebook (looks like mostly Isaac Salier-Hellendag) released what looks like a pretty sweet rich text editor written in React.
In the same vein:
- TinyMCE is the one that’s been around forever.
- ProseMirror is the fairly new one from Marijn Haverbeke
- ZenPen is a super minimal one from Tim Holman
- There’s been a bunch of attempts to replicate the Medium editor, like this.
If you don’t care about visual as-you-type formatting very much (i.e. you just want a simple Markdown editor) there are plenty of other simpler options you can search around for. And if you don’t need little helper buttons either, there is always <textarea>.