rules/advanced-event-handler-refs.md

---
title: Store Event Handlers in Refs
impact: LOW
impactDescription: stable subscriptions
tags: 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):**

```tsx
function useWindowEvent(event: string, handler: (e) => void) {
  useEffect(() => {
    window.addEventListener(event, handler)
    return () => window.removeEventListener(event, handler)
  }, [event, handler])
}
```

**Correct (stable subscription):**

```tsx
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:**

```tsx
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.