react-useeffect
1.4K
总安装量
376
周安装量
#282
全站排名
安装命令
npx skills add https://github.com/softaworks/agent-toolkit --skill react-useeffect
Agent 安装分布
claude-code
266
codex
265
gemini-cli
265
cursor
265
opencode
259
cline
258
Skill 文档
You Might Not Need an Effect
Effects are an escape hatch from React. They let you synchronize with external systems. If there is no external system involved, you shouldn’t need an Effect.
Quick Reference
| Situation | DON’T | DO |
|---|---|---|
| Derived state from props/state | useState + useEffect |
Calculate during render |
| Expensive calculations | useEffect to cache |
useMemo |
| Reset state on prop change | useEffect with setState |
key prop |
| User event responses | useEffect watching state |
Event handler directly |
| Notify parent of changes | useEffect calling onChange |
Call in event handler |
| Fetch data | useEffect without cleanup |
useEffect with cleanup OR framework |
When You DO Need Effects
- Synchronizing with external systems (non-React widgets, browser APIs)
- Subscriptions to external stores (use
useSyncExternalStorewhen possible) - Analytics/logging that runs because component displayed
- Data fetching with proper cleanup (or use framework’s built-in mechanism)
When You DON’T Need Effects
- Transforming data for rendering – Calculate at top level, re-runs automatically
- Handling user events – Use event handlers, you know exactly what happened
- Deriving state – Just compute it:
const fullName = firstName + ' ' + lastName - Chaining state updates – Calculate all next state in the event handler
Decision Tree
Need to respond to something?
âââ User interaction (click, submit, drag)?
â âââ Use EVENT HANDLER
âââ Component appeared on screen?
â âââ Use EFFECT (external sync, analytics)
âââ Props/state changed and need derived value?
â âââ CALCULATE DURING RENDER
â âââ Expensive? Use useMemo
âââ Need to reset state when prop changes?
âââ Use KEY PROP on component
Detailed Guidance
- Anti-Patterns – Common mistakes with fixes
- Better Alternatives – useMemo, key prop, lifting state, useSyncExternalStore