React parent component에서 child component에 method 호출하는 방법

• 꼭 아래 script를 html script로 추가해야 작동합니다.
• https://cdnjs.cloudflare.com/ajax/libs/react/15.3.2/react-dom.js
• https://cdnjs.cloudflare.com/ajax/libs/react/15.3.2/react-with-addons.js

class Child extends React.Component {
  componentDidMount() {
    this.props.onRef(this)
  }
  componentWillUnmount() {
    this.props.onRef(null)
  }
  method() {
    alert('do stuff')
  }
  render() {
    return 
Hello World!
  }
}

// Any higher-order component (HOC), for examle:
// withStyles https://github.com/kriasoft/isomorphic-style-loader
// connect https://github.com/reactjs/react-redux
// etc.
class EnhancedChild extends React.Component {
 render() {
    return 
  }
}

class Parent extends React.Component {
  onClick = () => {
    this.child.method() // do stuff
  };
  render() {
    return (
      
         (this.child = ref)} />
        
      
    );
  }
}

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