S06 L07 React Side Effects (Event Listener Example)

📘 REACT SIDE EFFECTS — EVENT LISTENER EXAMPLE In this lesson, we introduce React side effects using a practical active and inactive button example. You will toggle component state and use that state to register and deregister a keyboard event listener in the browser environment. 🎯 IN THIS VIDEO Understand what side effects are in React components Build an active and inactive toggle state flow Use conditional message rendering based on Boolean state Move click logic into a dedicated handler function Register a keyboard event listener when component is active Remove the keyboard event listener when component is inactive Log key press data from browser event objects Verify behavior through console output and state transitions 🚀 HOW TO USE THIS COURSE Side effects are essential when React components interact with external systems such as the DOM, APIs, or storage. This lesson sets up the mental model you need before learning effect lifecycle management and cleanup patterns. 👉 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 Any logic that touches external systems should be treated as a side effect and designed with clear setup and cleanup behavior.