Handling Memory Leaks in React with useEffect Hook and Cleanup Function
Quick question that's been bugging me - I'm attempting to set up I'm testing a new approach and This might be a silly question, but I'm facing an issue with memory leaks in my React application when using the `useEffect` hook. My component subscribes to a WebSocket connection to receive real-time data updates, and I want to make sure that the connection is properly closed when the component unmounts. However, I'm noticing that even after unmounting, the component still receives updates, which suggests that the subscription isn't being cleaned up correctly. Here’s a simplified version of my code: ```javascript import React, { useEffect, useState } from 'react'; const WebSocketComponent = () => { const [data, setData] = useState(null); useEffect(() => { const socket = new WebSocket('wss://my-websocket-server'); socket.onmessage = (event) => { const parsedData = JSON.parse(event.data); setData(parsedData); }; return () => { console.log('Cleaning up WebSocket connection'); socket.close(); }; }, []); return <div>{data ? JSON.stringify(data) : 'No data'}</div>; }; export default WebSocketComponent; ``` I have the `socket.close()` call in the cleanup function of `useEffect`, but I'm still seeing console log messages from the WebSocket after the component unmounts. I suspect this might be related to how React handles the event loop, but I’m not entirely sure. I’ve also ensured that my WebSocket server is not the one keeping the connection alive. What am I missing? Is there a different approach I should use to ensure that my subscriptions are cleaned up properly? I'm using React 17 and the WebSocket API. Any insights or suggestions would be greatly appreciated! For context: I'm using Javascript on Ubuntu. Any ideas what could be causing this? I'm working with Javascript in a Docker container on Windows 11. Could someone point me to the right documentation? I'm on Debian using the latest version of Javascript. Any feedback is welcome! This is for a web app running on Ubuntu 20.04. Has anyone else encountered this?