react - show hide element.jsx

class Child extends React.Component {
  render () {
    return (<div>I'm the child</div>);
  }
}

class ShowHide extends React.Component {
  constructor () {
    super ();
    this.state = {
      childVisible: false
    }
  }
  render () {
    return (
      <div>
        <div onClick={() => this.onClick()}>
          Parent = click me to show/hide my child
        </div>
        {
          this.state.childVisible
            ? <Child />
            : null
        }
      </div>
    )
  }

  onClick () {
    this.setState({childVisible: !this.state.childVisible});
  }
}

  ReactDOM.render(
      <ShowHide />,
    document.getElementById('container')
  )