component class react code example

Example 1: class in react

class App extends Component {
    constructor() {
        super()
        this.state = {
            name: "Sally",
            age: 13
        }
    }
    
    render() {
        return (
            

                
{this.state.name}
                
{this.state.age} years old
            
        )    
    }
}

Example 2: functional component react

function Welcome(props) {
  return 
Hello, {props.name}
;
}

function App() {
  return (
    

                      
  );
}

ReactDOM.render(
  ,
  document.getElementById('root')
);

Example 3: lifecycles if reactjs

class Clock extends React.Component {
  constructor(props) {
    super(props);
    this.state = {date: new Date()};
  }

  componentDidMount() {  }
  componentWillUnmount() {  }
  render() {
    return (
      

        
Hello, world!
        
It is {this.state.date.toLocaleTimeString()}.
      
    );
  }
}

Example 4: class component in react

class Car extends React.Component {
  render() {
    return 
Hi, I am a Car!
;
  }
}