Cleanup Functions in useEffect: Stop Leaks Before They Start

Introduction Almost everyone uses useEffect in React for fetching data, timers, or adding event listeners. The part that causes the most silent bugs is the cleanup function. Skip it or write it incorrectly and you get memory leaks, duplicate handlers firing, or the infamous setState on unmounte...

Source: [Dev.to](https://dev.to/naserrasouli/cleanup-functions-in-useeffect-stop-leaks-before-they-start-5h54)