useEffect

A Hook for performing side effects in function components. Runs after render. Can return a cleanup function.

Syntax

react

useEffect(() => { /* effect */ return () => { /* cleanup */ }; }, [deps])

Example

react

useEffect(() => {
  const controller = new AbortController();
  fetch("/api/data", { signal: controller.signal })
    .then(r => r.json())
    .then(setData);
  return () => controller.abort();
}, []);