gistfile1.js

export class Counter extends React.Component {
  static get propTypes() {
    return {
        initialCount: React.PropTypes.number 
    };
  }
  
  static get defaultProps() {
    return {
        initialCount: 1
    };
  }
  
  tick() {
    this.setState({count: this.state.count + 1});
  }
  
  render() {
    return (
      <div onClick={this.tick.bind(this)}>
        Clicks: {this.state.count}
      </div>
    );
  }
}