FRONTEND 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:
• Frontend Web Development Course — Section ...
📂 SECTION REPOSITORY
Section 6 repository:
https://github.com/RichardBrayCourses...
💡 NOTE
Any logic that touches external systems should be treated as a side effect and designed with clear setup and cleanup behavior.