👀 Views: 0 💬 Answers: 1 📅 Created: 2025-06-12

react hooks useEffect event-listener JavaScript

I'm confused about I've been banging my head against this for hours. I recently switched to I'm stuck on something that should probably be simple... I'm encountering a frustrating issue with loss of context in my React component when I set up an event listener inside the `useEffect` hook. I want to track mouse movements and update the state accordingly, but it seems that the `this` context is lost when the event is triggered. Here's my code snippet: ```javascript import React, { useEffect, useState } from 'react'; const MouseTracker = () => { const [position, setPosition] = useState({ x: 0, y: 0 }); useEffect(() => { const handleMouseMove = (event) => { setPosition({ x: event.clientX, y: event.clientY }); }; window.addEventListener('mousemove', handleMouseMove); return () => { window.removeEventListener('mousemove', handleMouseMove); }; }, []); return <div>Mouse Position: {position.x}, {position.y}</div>; }; export default MouseTracker; ``` When I render this component, it works for the first few movements, but after a while, it seems that `setPosition` stops being called, and I see stale values for `position`. I suspect that the closure is capturing an old state, but I'm not sure why that would happen here since I’m using functional updates. I've tried moving the `handleMouseMove` function outside of the `useEffect` to see if that would help, but it didn't change the behavior. I also checked for any possible memory leaks and confirmed that the cleanup was being called properly. I'm using React version 17.0.2. Any advice on how to resolve this context loss issue would be greatly appreciated! The project is a service built with Javascript. I'm open to any suggestions. For context: I'm using Javascript on Windows 10. Any examples would be super helpful.