HouYunFei
fb79a15508
- 添加 sections 定义文件，包含性能优化各领域分类 - 添加规则模板文件，规范文档结构和标签定义 - 添加异步操作优化规则，包括防止瀑布流、并行化、延迟等待等 - 添加包大小优化规则，包括避免桶式导入、动态导入、预加载等 - 添加服务端性能优化规则，包括 API 路
56 lines
1.4 KiB
Markdown
56 lines
1.4 KiB
Markdown
---
|
|
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.
|