react.component

class App extends Component {
    constructor() {
        super()
        this.state = {
            name: "Sally",
            age: 13
        }
    }
    
    render() {
        return (
            <div>
                <h1>{this.state.name}</h1>
                <h3>{this.state.age} years old</h3>
            </div>
        )    
    }
}

class Welcome extends React.Component {
  render() {
    return <h1>Hello, {this.props.name}</h1>;
  }
}

import React from 'react'; const App = () => {  const greeting = 'Hello Function Component!';   return <Headline value={greeting} />;}; const Headline = ({ value }) =>  <h1>{value}</h1>; export default App;

componentDidMount()

componentDidUpdate(prevProps, prevState, snapshot)

class Welcome extends React.Component {
  render() {
    return <h1>Bonjour, {this.props.name}</h1>;
  }
}

npx create-react-app my-app --scripts-version [email protected]

const element = <div />;