S06 L09 React Introducing useEffect

📘 REACT INTRODUCING USEEFFECT In this lesson, we introduce useEffect as React’s mechanism for handling side effects outside the component function body. You will learn the core execution flow: component render, effect execution, cleanup on dependency changes, and cleanup on unmount. 🎯 IN THIS VIDEO Refactor click toggling logic to simplify component code Understand why side effects should not run inside the render body Add logging to observe component render flow Define an effect function and pass it to useEffect Import and call useEffect correctly in a component Return a cleanup function from the effect Observe cleanup when the component unmounts Use dependency arrays to rerun effects when state changes 🚀 HOW TO USE THIS COURSE useEffect is essential for safe interaction with external systems in React. This lesson gives the lifecycle model you need before implementing real listener setup and teardown logic. 👉 Course Website: www.richardbraycourses.co.uk 👉 Course Repositories: www.github.com/RichardBrayCourses 👉 Full course playlist: https://youtube.com/playlist?list=PLNlOxdq7xu14b5ewH4IJC9tMinkgZBuVR&si=Pg8pEDR5UUbQstz6 📂 SECTION REPOSITORY Section 6 repository: https://github.com/RichardBrayCourses/frontend06-react 💡 NOTE A cleanup function returned from useEffect runs before the next effect cycle and also during unmount, which prevents lingering side effects.