Markdium-React state update on an unmounted component

Markdium-JSX.jsx

function App() {
  const [showPets, setShowPets] = useState(true);

  const toggle = () => {
    setShowPets(state => !state);
  };

  return (
    <div>
      <button onClick={toggle}>{showPets ? "hide" : "show"}</button>
      {showPets && <Pets />}
    </div>
  );
}