React is a popular JavaScript framework for creating front-end applications, such as user interfaces that allow users to interact with programs. Originally created by Facebook, it has gained popularity by allowing developers to create fast applications using an intuitive programming paradigm that ties JavaScript with an HTML-like syntax known as JSX.
In this series, you will build out examples of React projects to gain an understanding of this framework, giving you the knowledge you need to pursue front-end web development or start out on your way to full stack development.
Source:
https://www.digitalocean.com/community/tutorial_series/how-to-code-in-react-js