Every now and then I use software tools where rather than complaining about how x or y should be different, everything seems to be the best possible version of something I'd have come up with myself, and I have zero complaints. Mithril.js is one of those tools.
Participating in the project via Gitter was very welcoming as well. Long live Mithril!
Would they not want your solution to conform to existing solutions; which (regardless of being idiomatic to React) would be idiomatic to the codebase?
It's not many hands on one project but everyone taking care of their own projects, so it's a bit different where I'm at right now.
Another good skill to have though, that is unfortunately not super duper common either, is being able to figure out and match conventions and patterns in code bases when introducing changes.