The problem with the javascript frameworks is that they are NOT perfect search engine friendly. Although Google can crawl and index Ajax content but it is not so reliable and need to follow the guidelines. The advantage of React.js is that you can run it on the server and the virtual DOM will be rendered and returned to the browser as a regular web page. In this post, we will implement a sample in ASP.NET to pre-render the initial state of your React components server-side and the outcome is already rendered page of markup. So it will be indexed just like any other static page by search engine.

If you are new to React.js, I strongly recommend to read following tutorial:

React.js: Introduction and Hello World with ASP.NET MVC 5