function App () {

  const [count1, setCount1] = React.useState(1) 

  let count2 = 1

  const handleIncrement1 = () => {

    // we trigger a re-render by setting a new state

    setCount1(count1 + 1)

  }

  const handleIncrement2 = () => {

    // nothing happens!

    count2++

  }

  return (

    <div>

      Reactive count: {count1}

      <br />

      <button onClick={handleIncrement1}>

        Handle increment reactive count

      </button>

      <br />

      Static count: {count2}

      <br />

      <button onClick={handleIncrement2}>

        Handle increment static count

      </button>

    </div>

  )

}