This little repo is designed to gently introduce developers into the wonderful world of React. Each demo's source is annotated with comments and can be read basically top-to-bottom.
The demos are available online.
Clone the repository and open build/index.html in your browser; the demos are pre-built and checked in to the repo.
Requires Node.js.
npm install && npm start
Then open build/index.html in your browser. The Node process will automatically recompile the demos on any change; check your console output for syntax errors.
The React site has a ton of info, and I recommend checking it out. It also contains more in-depth API documentation.
The "Top-Down Data Flow & shouldComponentUpdate" demo introduces the idea of a top-level data store that causes an application-wide re-render whenever its data changes; this is a nice stepping stone to the flux architecture, including flux libraries like Fluxxor.