ReactJS is an open-source JavaScript library that brings the power of reactive programming to web applications and sites. It aims to address the challenges encountered in developing single-page applications, and is intended to help developers build large, easily scalable and changing web apps. Starting with a project on Open Library API, you will be introduced to React and JSX before moving on to learning about the life cycle of a React component. In the second project, building a multi-step wizard form, you will learn about composite dynamic components and perform DOM actions. You will also learn about building a fast search engine by exploring server-side rendering in the third project on a search engine application. Next, you will build a simple frontpage for an e-commerce app in the fourth project by using data models and React add-ons. In the final project you will develop a complete social media tracker by using the flux way of defining React apps and know about the best practices and use cases with the help of ES6 and redux.