React Base Fiddle (JSX)

Starting point for creating JSFiddles with React. This uses React with Addons.

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/babel-core/5.8.24/browser.js"></script>
<script src="https://npmcdn.com/react@latest/dist/react-with-addons.js"></script>
<script src="https://npmcdn.com/react-dom@latest/dist/react-dom.js"></script>
<script src="https://facebook.github.io/react/js/jsfiddle-integration-babel.js"></script>

<div id="container">
    <!-- This element's contents will be replaced with your component. -->
</div>

JavaScript 1.7

class CounterService {
  constructor() {
    this.counter = 0
    this.observers = []
    this.tic = this.tic.bind(this)
    this.subscribe = this.subscribe.bind(this)
    this.notify = this.notify.bind(this)
    this.notifyAll = this.notifyAll.bind(this)
    setInterval(this.tic, 1000)
  }
  
  subscribe(observer) {
    this.observers.push(observer)
    this.notify(observer)
  }
  
  notify(observer) {
  	observer.next(this.counter)
  }
  
  notifyAll() {
    this.observers.forEach(this.notify)
  }
  
  tic() {
  	this.counter += 1
    this.notifyAll()
    console.log(this.counter)
  }
  
}

const ServiceSingleton = new CounterService()

const CounterServiceConnector = (Component) => {
  return class ConnectedComponent extends React.Component {
    constructor(props){
      super(props)
      this.state = {
        counter: 0
      }
    }

    componentDidMount() {
      ServiceSingleton.subscribe({
        next: counter => this.setState({ counter })
      })
    }

    render() {
      const { counter } = this.state
      return <Component counter={counter}/>
    }
  }
} 

const Counter = CounterServiceConnector(({ counter }) => {
 return <div>You're looking at this counter since {counter}s</div>
})

const CounterV2 = CounterServiceConnector(({ counter }) => {
 return <div>You're looking at this counter 2 since {counter}s</div>
})

const Demo = () => {
 return <div><Counter/><CounterV2/></div>
}

ReactDOM.render(
  <Demo />,
  document.getElementById('container')
);