const root = document.getElementById("root");

let counter = 0;
function countUp() {
  counter = counter +1;
  
  render();
}
function render() {
  ReactDOM.render(<Container />, root);
}

const Container = () => (
  <div>
    <h3>Total clicks: {counter}</h3>
    <button onClick={countUp}>Click me</button>
  </div>
);

render();