react-use-effect SKILL.md skillA
react-use-effect from ncaq/konoka is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add ncaq/konoka/react-use-effect@git:20260409.2fb1d0ePins git:20260409.2fb1d0e in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- ncaq/konoka
- Path
plugins/web-tasuke/skills/react-use-effect/SKILL.md- Versions recorded
- 3
- Latest version
- git:20260409.2fb1d0e, committed Apr 9, 2026
- First version recorded
- Apr 7, 2026
- Size
- 3,574 bytes
- Repository stars
- 3
- License
- Apache-2.0
Rules for useEffect usage in React including when to avoid it and when to extract it into custom hooks. Use when writing or reviewing React components that contain or might need useEffect.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# useEffectの使いどころを見極める
`useEffect`は外部システム(ブラウザAPI、ネットワーク、サードパーティライブラリ)との同期にのみ使います。
それ以外の用途では、より適切な代替手段がないか検討してください。
参考: [You Might Not Need an Effect](https://react.dev/learn/you-might-not-need-an-effect)
## useEffectを使わずに解決するパターン
### レンダリング用のデータ変換は直接計算します
```tsx
// Bad: useEffectでstateを更新
const [fullName, setFullName] = useState("");
useEffect(() => {
setFullName(firstName + " " + lastName);
}, [firstName, lastName]);
// Good: レンダリング中に計算
const fullName = firstName + " " + lastName;
```
### ユーザー操作の処理はイベントハンドラで行います
```tsx
// Bad: useEffectで副作用を検知
useEffect(() => {
if (product.isInCart) {
showNotification(`Added ${product.name} to cart!`);
}
}, [product]);
// Good: イベントハンドラで直接処理
function handleBuyClick() {
addToCart(product);
showNotification(`Added ${product.name} to cart!`);
}
```
### propsが変わったときの状態リセットにはkeyを使います
```tsx
// Bad: useEffectでリセット
useEffect(() => {
setComment("");
}, [userId]);
// Good: keyでコンポーネントを再マウント
<Profile userId={userId} key={userId} />;
```
### 高コストな計算のキャッシュにはuseMemoを使います
```tsx
// Bad: useEffectで計算結果をstateに保存
useEffect(() => {
setFilteredTodos(getFilteredTodos(todos, filter));
}, [todos, filter]);
// Good: useMemoでキャッシュ
…Read the whole file at its exact version.
How to install
mdr add ncaq/konoka/react-use-effect@sha256:15adf08536ae5cceThe line at the top of this page pins the label git:20260409.2fb1d0e, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_xuen2eovouoktasz)
1 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 3 versions of this file, between Apr 7, 2026 and Apr 9, 2026, more than one a day.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20260409.2fb1d0e latest | 2026-04-09 | 2fb1d0e | 3,574 B | A | view · diff |
| git:20260409.6cc9c33 | 2026-04-09 | 6cc9c33 | 3,562 B | A | view · diff |
| git:20260407.8cdba48 | 2026-04-07 | 8cdba48 | 2,871 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (3574 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
ncaq/konoka · 3 stars · license Apache-2.0 · pushed 2026-10-19 · branch master
API
GET https://markdownregistry.com/api/v1/artifacts/art_xuen2eovouoktasz GET https://markdownregistry.com/api/v1/resolve?ref=ncaq/konoka/react-use-effect GET https://markdownregistry.com/api/v1/blob/15adf08536ae5cce9f97e7180f1d4fa2e256e49d2d9635e6e8da52371db2d4ca
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.