const handleSubmit = e => {
  e.preventDefault();
  // ...
};

const ReviewPopup = ({ name }) => {
  const [messageShown, setMessageShown] = useState(false);
  const hideMessage = () => {
    setMessageShown(false);
  };

  return (
    <form onSubmit={handleSubmit} className="new_review" id="new_review" action="/reviews" acceptCharset="UTF-8" method="post">
    // ...
    </form>
  );
};