react lifecycle_error ai_generated true

Warning: Can't perform a React state update on an unmounted component

ID: react/useeffect-cleanup-memory-leak

Also available as: JSON · Markdown
90%Fix Rate
90%Confidence
50Evidence
2023-01-01First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
18 active — — —

Root Cause

State update after component unmount. Missing cleanup in useEffect for async operations.

generic

Workarounds

  1. 95% success Return a cleanup function from useEffect with AbortController 
    useEffect(() => {
  const ctrl = new AbortController();
  fetch(url, { signal: ctrl.signal }).then(...);
  return () => ctrl.abort();
}, [url]);

    Sources: https://react.dev/reference/react/useEffect#fetching-data-with-effects

  2. 92% success For subscriptions, unsubscribe in cleanup: return () => unsubscribe() 
    return () => unsubscribe()

    Sources: https://react.dev/reference/react/useEffect#connecting-to-an-external-system

Dead Ends

Common approaches that don't work:

  1. Ignore the warning — it's just a warning 65% fail

    Causes memory leaks and wasted computation

  2. Use a global isMounted flag 70% fail

    Anti-pattern — use AbortController or cleanup function instead

Error Chain

Frequently confused with: