react-rails makes it easy to use React and JSX in your Ruby on Rails
application.  It can

- provide various react builds to your asset bundle
- transform .jsx in the asset pipeline
- render components into views and mount them via view helper and react_ujs
- render components server-side with prerender: true
- generate components with a Rails generator
- be extended with custom renderers, transformers and view helpers

WWW: https://github.com/reactjs/react-rails