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1.5 KiB
1.5 KiB
title, impact, impactDescription, tags
| title | impact | impactDescription | tags |
|---|---|---|---|
| Store Event Handlers in Refs | LOW | stable subscriptions | advanced, hooks, refs, event-handlers, optimization |
Store Event Handlers in Refs
Store callbacks in refs when used in effects that shouldn't re-subscribe on callback changes.
Incorrect (re-subscribes on every render):
function useWindowEvent(event: string, handler: (e) => void) {
useEffect(() => {
window.addEventListener(event, handler);
return () => window.removeEventListener(event, handler);
}, [event, handler]);
}
Correct (stable subscription):
function useWindowEvent(event: string, handler: (e) => void) {
const handlerRef = useRef(handler);
useEffect(() => {
handlerRef.current = handler;
}, [handler]);
useEffect(() => {
const listener = (e) => handlerRef.current(e);
window.addEventListener(event, listener);
return () => window.removeEventListener(event, listener);
}, [event]);
}
Alternative: use useEffectEvent if you're on latest React:
import { useEffectEvent } from 'react';
function useWindowEvent(event: string, handler: (e) => void) {
const onEvent = useEffectEvent(handler);
useEffect(() => {
window.addEventListener(event, onEvent);
return () => window.removeEventListener(event, onEvent);
}, [event]);
}
useEffectEvent provides a cleaner API for the same pattern: it creates a stable function reference that always calls the latest version of the handler.