I use atom as an editor for markdown. But I don't know about if they're using React in it or not. I don't follow the dev that closely. I am still rather sure you can develop plugins in react, which is fine.

My point being that require('react'); wasn't the best fit for their editor window (which doesn't need events to be intercepted, etc), but the idea behind virtual dom diffing and how they updated their window left an impact. The concepts behind react got them thinking in a new way, which is ultimately much more important than their dependency on a 0.x.y release library.

If anything, the design of react was a stepping stone to where they've ended up now. It wasn't "bad", so much as unoptimized for their specific task. For me I'm glad it can intercept events (usually), since it simplifies cross browser compatibility. Atom is essentially one browser version, so it doesn't need that overhead.

Atom doesn't use React any longer for their editor component

> React is a great tool for many cases, for our particular needs in this particular case I decided it would be easier to just do things for ourselves.

https://github.com/atom/atom/pull/5624