Handling Memory Leaks in React with useEffect and Cleanup in Heavy Component Trees
I can't seem to get I've searched everywhere and can't find a clear answer... After trying multiple solutions online, I still can't figure this out. I'm experiencing important performance optimization with my React application, particularly with a component that renders a large tree of child components... The parent component uses `useEffect` to manage subscriptions to an external data source, but I'm worried that it's causing memory leaks due to the way I'm handling the cleanup function. My `useEffect` looks like this: ```javascript useEffect(() => { const subscription = dataSource.subscribe(data => { setData(data); }); return () => { subscription.unsubscribe(); // Also want to clear state and any listeners setData([]); }; }, [dataSource]); ``` The question I'm working with is that even though I've added a cleanup function, it seems that the component does not completely unmount, and I still see increasing memory usage in the browser's performance tab. I've tried moving `setData([])` outside the cleanup, but that led to my UI showing stale data until the next subscription update. Additionally, I noticed that there are some warnings in the console about "too many re-renders" when I attempt to conditionally render based on the state of the data; this happens when the data updates too quickly. I know that React components can re-render often, but Iām not sure how to optimize my `useEffect` to truly clean up and prevent these memory leaks. Are there better practices for managing subscriptions, especially when dealing with large component trees? Any guidance or best practices would be greatly appreciated! For context: I'm using Javascript on macOS. What's the best practice here? My development environment is macOS. Am I missing something obvious? This issue appeared after updating to Javascript 3.9. Is there a better approach?