function App() {

   const [toggle, setToggle]=React.useState(false);
   const [count, setCount]=React.useState(0);
   
   function handleClick(e) {
     setToggle(toggle ? false : true);
     setCount(count+1);
   }
  
  let cycle = null;
  if (toggle) {
    cycle = <LifeCycle count={count}/>;
  } 
  return (
      <div>
        <h1>Mount/Unmount/Update Demo</h1>
        <button type="button" onClick={handleClick}>{toggle ? 'Unmount the lifecycle component' : 'Mount the lifecycle component'}</button>
        {cycle}
  </div>
  );
}