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React.js Commands & Tips

Common React.js snippets and CLI commands.

Action Command Details
Create React app npx create-react-app my-app Bootstrap a new React project.
Start dev server npm start Run development server.
Build project npm run build Build optimized production bundle.
Functional component const MyComp = () => <div>Hello</div>; Define a React functional component.
Class component class MyComp extends React.Component { render() { return <div>Hello</div>; } } Define a React class component.
useState hook const [state, setState] = useState(initialValue); Add local state to functional components.
useEffect hook useEffect(() => { /* side effect */ }, []); Perform side effects in functional components.
Props <Component prop1={value} /> Pass data to components.
Event handler <button onClick={handleClick}>Click me</button> Handle events.
JSX fragment <> ... </> Group multiple elements without extra node.
Conditional rendering {condition && <Component />} Render component conditionally.
List rendering {items.map(item => <li key={item.id}>{item.name}</li>)} Render lists dynamically.
React Router start npm install react-router-dom Install routing library.
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