React - optimise creation of new functions in render

react.jsx

class SayHi extends Component {
  // We can't use showMessage directly because it creates
  // a new event handler every time you call it.
  showMessage = (msg) => (e) => {
   console.log(`Say ${msg}`, e)
  }
  
  // So instead, we need to create the event handlers beforehand,
  // then call those inside of `render`.
  showHiMessage = this.showMessage('Hi')
 
  render () {
   return (
      <Button onClick={this.showHiMessage}>
            Click Me
      </Button>
    );
  }
}