excerpt from timer app

timer.js

    <div className="App">
      <header className="App-header">
        <h2>Timers completed: {completed}</h2>
        <h2>{timer.value}</h2>
        <div>
          <Button onClick={timer.start}>Start</Button>
          <Button onClick={timer.stop}>Stop</Button>
        </div>
        <div>
          <Button onClick={timer.skip}>Skip</Button>
          <Button onClick={timer.reset}>Reset</Button>
        </div>
      </header>
    </div>