reactBindBad.js

class BuildingBlock extends React.Component {
  constructor(props) {
    super(props);
    
    this.handleClick = this.handleClick.bind(this);
  }
  
  handleClick() {
    console.log('click!');
  }

  render() {
    return (
      <button onClick={this.handleClick}/>
    );
  }
}