Well, you can use Haxe with React Native instead of plain Javascript.
If you are looking for a way to build mobile apps, you can try HaxeUI v2, based on OpenFL.
http://haxeui.org/
Haxe is a programming language and should be compared to as3. It is much more powerful and can compile to 12 targets including JavaScript,php, c++, and as3.
OpenFL is a cross-plateform port of the flash API in Haxe.
All this flash stuff are just a part of an amazing technology.