JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.6.1/react.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/15.6.1/react-dom.js"></script>
<section class="app"></section>

Babel + JSX

class Example extends React.Component {

  constructor(props) {
    super(props);
    this.state = { progress: "0", score: 0};
    this.handleClick = this.handleClick.bind(this);
    this.scoreUpdate = this.scoreUpdate.bind(this);
  }

  handleClick(e) {
    let previous = this.state.progress;
    let score = Number(e.currentTarget.id);
    this.setState({progress: previous+e.currentTarget.id});
    this.scoreUpdate(score);
  }  

  scoreUpdate(score) {
  	console.log(this.state.progress);
    if (this.state.progress.length % 3 == 0) {
      let previous = this.state.score;
      this.setState({score: previous+score});
    }
  }

  render() {
  	return (
    	<button onClick={this.handleClick} id="1">
        {this.state.score}: Click Me...
      </button>
    );
  }
  
}

ReactDOM.render(<Example />, document.querySelector('section.app'));