React’s components let you build and share code in a reusable fashion. Think of them like Lego blocks – each piece of code is reusable – and when assembled together, form an application’s user interface. Each component has its own set of properties, and when a user interacts with the interface, the state changes.

React’s programming model allows it to change state automatically when data is updated. Its library is lightweight (less than 6kb when gzipped), and testing is a breeze. Unlike traditional UI browser tests, you can test React components directly using the node command line. Just add the corresponding script to your website’s index file and run your application. The application will render a Hello World page.

React’s virtual DOM enables it to update the DOM quickly. Instead of reloading the entire page, React only re-renders the sections that need to change. This helps the browser to load a page faster. In addition, React’s client-side routing ensures that the entire page does not need to be reloaded.

React has a strong community. Facebook heavily uses the framework and has over 50k React components in production. Its developers contribute to GitHub, and the team publishes blog posts for every release.