사용 방법
- 설치 명령을 복사하고 자신의 에이전트 환경에 설치하기 전에 소스 패키지를 확인하세요.
- 필요한 도구, 인증 정보, 지원 환경은 원본 문서에서 확인하세요.
- 입력과 원하는 산출물을 설명하고 출처와 결과를 대조하세요.
npx skills add https://github.com/wshobson/agents --skill react-modernization시작 전 확인
- 설치에는 모델 구독, API 한도, 파일 접근 권한이 포함되지 않습니다.
- 별점 수와 설치 수는 활동 지표이며 독립적인 품질·보안 검증이 아닙니다.
원본 Skill 문서
원본 저장소의 제목, 예시, 코드, 표, 링크, 이미지를 유지해 표시합니다.
React Modernization
Master React version upgrades, class to hooks migration, concurrent features adoption, and codemods for automated transformation.
When to Use This Skill
- Upgrading React applications to latest versions
- Migrating class components to functional components with hooks
- Adopting concurrent React features (Suspense, transitions)
- Applying codemods for automated refactoring
- Modernizing state management patterns
- Updating to TypeScript
- Improving performance with React 18+ features
Version Upgrade Path
React 16 → 17 → 18
Breaking Changes by Version:
React 17:
- Event delegation changes
- No event pooling
- Effect cleanup timing
- JSX transform (no React import needed)
React 18:
- Automatic batching
- Concurrent rendering
- Strict Mode changes (double invocation)
- New root API
- Suspense on server
Class to Hooks Migration
State Management
javascript
// Before: Class component
class Counter extends React.Component {
constructor(props) {
super(props);
this.state = {
count: 0,
name: "",
};
}
increment = () => {
this.setState({ count: this.state.count + 1 });
};
render() {
return (
<div>
<p>Count: {this.state.count}</p>
<button onClick={this.increment}>Increment</button>
</div>
);
}
}
// After: Functional component with hooks
function Counter() {
const [count, setCount] = useState(0);
const [name, setName] = useState("");
const increment = () => {
setCount(count + 1);
};
return (
<div>
<p>Count: {count}</p>
<button onClick={increment}>Increment</button>
</div>
);
}Lifecycle Methods to Hooks
javascript
// Before: Lifecycle methods
class DataFetcher extends React.Component {
state = { data: null, loading: true };
componentDidMount() {
this.fetchData();
}
componentDidUpdate(prevProps) {
if (prevProps.id !== this.props.id) {
this.fetchData();
}
}
componentWillUnmount() {
this.cancelRequest();
}
fetchData = async () => {
const data = await fetch(`/api/${this.props.id}`);
this.setState({ data, loading: false });
};
cancelRequest = () => {
// Cleanup
};
render() {
if (this.state.loading) return <div>Loading...</div>;
return <div>{this.state.data}</div>;
}
}
// After: useEffect hook
function DataFetcher({ id }) {
const [data, setData] = useState(null);
const [loading, setLoading] = useState(true);
useEffect(() => {
let cancelled = false;
const fetchData = async () => {
try {
const response = await fetch(`/api/${id}`);
const result = await response.json();
if (!cancelled) {
setData(result);
setLoading(false);
}
} catch (error) {
if (!cancelled) {
console.error(error);
}
}
};
fetchData();
// Cleanup function
return () => {
cancelled = true;
};
}, [id]); // Re-run when id changes
if (loading) return <div>Loading...</div>;
return <div>{data}</div>;
}Context and HOCs to Hooks
javascript
// Before: Context consumer and HOC
const ThemeContext = React.createContext();
class ThemedButton extends React.Component {
static contextType = ThemeContext;
render() {
return (
<button style={{ background: this.context.theme }}>
{this.props.children}
</button>
);
}
}
// After: useContext hook
function ThemedButton({ children }) {
const { theme } = useContext(ThemeContext);
return <button style={{ background: theme }}>{children}</button>;
}
// Before: HOC for data fetching
function withUser(Component) {
return class extends React.Component {
state = { user: null };
componentDidMount() {
fetchUser().then((user) => this.setState({ user }));
}
render() {
return <Component {...this.props} user={this.state.user} />;
}
};
}
// After: Custom hook
function useUser() {
const [user, setUser] = useState(null);
useEffect(() => {
fetchUser().then(setUser);
}, []);
return user;
}
function UserProfile() {
const user = useUser();
if (!user) return <div>Loading...</div>;
return <div>{user.name}</div>;
}React 18 Concurrent Features
New Root API
javascript
// Before: React 17
import ReactDOM from "react-dom";
ReactDOM.render(<App />, document.getElementById("root"));
// After: React 18
import { createRoot } from "react-dom/client";
const root = createRoot(document.getElementById("root"));
root.render(<App />);Automatic Batching
javascript
// React 18: All updates are batched
function handleClick() {
setCount((c) => c + 1);
setFlag((f) => !f);
// Only one re-render (batched)
}
// Even in async:
setTimeout(() => {
setCount((c) => c + 1);
setFlag((f) => !f);
// Still batched in React 18!
}, 1000);
// Opt out if needed
import { flushSync } from "react-dom";
flushSync(() => {
setCount((c) => c + 1);
});
// Re-render happens here
setFlag((f) => !f);
// Another re-renderTransitions
javascript
import { useState, useTransition } from "react";
function SearchResults() {
const [query, setQuery] = useState("");
const [results, setResults] = useState([]);
const [isPending, startTransition] = useTransition();
const handleChange = (e) => {
// Urgent: Update input immediately
setQuery(e.target.value);
// Non-urgent: Update results (can be interrupted)
startTransition(() => {
setResults(searchResults(e.target.value));
});
};
return (
<>
<input value={query} onChange={handleChange} />
{isPending && <Spinner />}
<Results data={results} />
</>
);
}Suspense for Data Fetching
javascript
import { Suspense } from "react";
// Resource-based data fetching (with React 18)
const resource = fetchProfileData();
function ProfilePage() {
return (
<Suspense fallback={<Loading />}>
<ProfileDetails />
<Suspense fallback={<Loading />}>
<ProfileTimeline />
</Suspense>
</Suspense>
);
}
function ProfileDetails() {
// This will suspend if data not ready
const user = resource.user.read();
return <h1>{user.name}</h1>;
}
function ProfileTimeline() {
const posts = resource.posts.read();
return <Timeline posts={posts} />;
}Additional patterns and templates
More detailed templates and worked examples live in references/details.md. Read that file for the full pattern library.
