When learning React, one of the most important hooks you’ll encounter is useEffect . It's essential for managing side effects like fetching data, updating the DOM, or setting timers. However, as a beginner, you might run into issues such as unexpected re-renders or infinite loops, which can make it tricky to work with. In this guide, we’ll break down the what , where , when , and why of useEffect , and dive into common mistakes you should avoid. I’ll also provide sample code to help you understand these concepts better. What is useEffect ? useEffect is a React hook that lets you perform side effects in function components. Side effects include things like: Fetching data from an API Manually interacting with the DOM Subscribing to events (e.g., setting up intervals) useEffect ( () => { // Side effect logic here }); The code inside useEffect runs after the component renders , and it can re-run if de...