react-useeffect
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.
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Install
Works with every agent the skills CLI supports.
npx skills add https://github.com/softaworks/agent-toolkit --skill react-useeffect- 01
Install
Run the command in your project. The CLI asks which agents to install for.
- 02
Describe the task
Ask your agent for something this skill covers. It loads react-useeffect automatically when relevant.
- 03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.
Security audits
Independent scans of the skill's instructions and bundled files.
SKILL.md
The instructions your agent reads when the skill is triggered.
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?
├── 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
Detailed Guidance
- Anti-Patterns - Common mistakes with fixes
- Better Alternatives - useMemo, key prop, lifting state, useSyncExternalStore
FAQ
What does the react-useeffect skill do?
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.
How do I install react-useeffect?
Run npx skills add https://github.com/softaworks/agent-toolkit --skill react-useeffect in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/react-useeffect/ (personal) or .claude/skills/react-useeffect/ (project).
Which AI agents can use react-useeffect?
Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.
Is react-useeffect safe to install?
Security partners have reviewed it: Gen Agent Trust Hub passed; Socket passed; Snyk passed; Runlayer passed; ZeroLeaks passed. As with any skill, read the SKILL.md and bundled scripts before installing.
Who maintains react-useeffect?
It is published by softaworks in softaworks/agent-toolkit. It has 4,065 recorded installs.
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