react-modernization

# 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 ...