React is definitely one of the most talked about libraries on the web. It has become as popular as jQuery was in its prime, and more and more developers choose it to build the user interface of their web applications. Why has it become so popular? Why is this JavaScript library so innovative compared to others?

We will try to provide answers to these questions in this book by showing what the library offers, and by using it to build efficient web user interfaces.

In this chapter, we will introduce React and we will start building the basic infrastructure of a React-based application. Then, we will analyze how to design a user interface so that it can be easily mapped to React components, exploiting the best from React's internal architecture.

By the end of this chapter, you will be able to:

• Describe what React is and where it fits in the development of your applications
• Set up the infrastructure of a React-based application
• Design the UI of your application, optimizing it for use in React