Agent Skills › softaworks/agent-toolkit › react-useeffect

react-useeffect

GitHub

提供React useEffect最佳实践，指导何时使用或避免Effect，涵盖派生状态、数据获取及外部系统同步等场景，推荐useMemo等替代方案。

skills/react-useeffect/SKILL.md softaworks/agent-toolkit

触发场景

编写或审查React useEffect逻辑处理派生状态与副作用同步优化React组件性能

安装

npx skills add softaworks/agent-toolkit --skill react-useeffect -g -y

更多选项

不安装直接使用

npx skills use softaworks/agent-toolkit@react-useeffect

指定 Agent (Claude Code)

npx skills add softaworks/agent-toolkit --skill react-useeffect -a claude-code -g -y

安装 repo 全部 skill

npx skills add softaworks/agent-toolkit --all -g -y

预览 repo 内 skill

npx skills add softaworks/agent-toolkit --list

SKILL.md

Frontmatter

{
    "name": "react-useeffect",
    "description": "React useEffect best practices from official docs. Use when writing\/reviewing useEffect, useState for derived values, data fetching, or state synchronization. Teaches when NOT to use Effect and better alternatives."
}

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 useSyncExternalStore when 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?
├── User interaction (click, submit, drag)?
│   └── Use EVENT HANDLER
├── Component appeared on screen?
│   └── Use EFFECT (external sync, analytics)
├── Props/state changed and need derived value?
│   └── CALCULATE DURING RENDER
│       └── Expensive? Use useMemo
└── Need to reset state when prop changes?
    └── Use KEY PROP on component