React is today's most popular open-source JavaScript library for front-end web application development. React Programming: The Big Nerd Ranch Guide helps programmers with experience in HTML, CSS, and JavaScript master React through hands-on examples. Based on Big Nerd Ranch's popular React Essentials bootcamp, this guide illuminates key concepts with realistic code, guiding you step by step through building a starter app and a complete, production-ready app, both crafted to help you quickly leverage React's remarkable power. Use React to write reliable, declarative code, create carts and other e-commerce features, optimize performance, and gain experience with component and end-to-end testing. Along the way, you will learn to use tools like Create React App, functional components, hooks, ESLint, React Router, websockets, the React Testing Library, and Cypress.