[Tutorial] State

■ HTML / JSP

■ JS(ES6/Babel)

class Counter extends React.Component{
  
  constructor(props) {
    super(props);
    this.state= {
      value: 0
    };
    this.handleClick = this.handleClick.bind(this);
  }
  
  handleClick() {
    this.setState({
      value: this.state.value+1
    });
  }
  
  render() {
    return (
      

        
{this.state.value}
        
      
    );
  }
}

class App extends React.Component {
  render() {
    return (
      
    );
  }
}
      
ReactDOM.render(
  I am React.js
  , document.getElementById('root'));

※ 대문자 변경

<app>I am React.js</app> →  <App>I am React.js</App>

<codelab> → <Codelab>

<counter> → <Counter>

※ 맨 마지막 <counter/> 삭제