Note: This is recorded with an older version of React and many things have changed. The core concepts are still accurate, but there are some technical differences you’ll need to work through.
This course serves as an excellent reference for React Class Components. This can be very useful for legacy code bases.
React is a "javascript library for building user interfaces" from the fine folks at Facebook & Instagram. It strictly focuses on the "V" in your MVC applications, and touts a blazing fast virtual DOM diff implementation.
This series will explore the basic fundamentals of React to get you started.
When you've finished with this series, be sure to check out React: Flux Architecture (ES6) for real-world React application development.