`Run Effect once onMount + Cleanup Function` ↔ call `useEffect()` with empty Deps Array & return Cleanup Function

useEffect(() => {
    DO_SOMETHING()
    return () => CLEANUP()
  }, [] );

return () ⇒ clearInterval()

return () ⇒ clearTimeout()

return () ⇒ removeListener(); to unmount event

to cancel request on unmount using AbortController

useEffect(() => {
    const controller = new AbortController()
    fetch(url, {controller})
      .then(data => //handle data);
    () => controller.abort();
  }, [] )

create controller inside effect

pass into controller into fetch

call in cleanup function

Run Effect once onMount + Cleanup Function ↔ call useEffect() with empty Deps Array & return Cleanup Function

References​

`Run Effect once onMount + Cleanup Function` ↔ call `useEffect()` with empty Deps Array & return Cleanup Function

References