code:

interface Props {
  message: string;
  optionalMessage?: string;
}

interface State: {
  shouldShowButton: boolean;
}

class MyComponent extends React.PureComponent<Props, State>  {
  state: State = {
    shouldShowButton: false,
  }

  render() {
    return (
      <React.Fragment>
        <div>{props.message}</div>
        {props.optionalMessage} && <div>{optionalMessage}</div>
        {this.state.shouldShowButton} && <button />
       </React.Fragment>
     )
  }
}