NewBook(bookName)}, null),
      e(BookList, {books: this.state.books}, null),
      e(ButtonGrid, null, null),
      e('div', {ref: this.mountPoint}, null),
    );
  }

  onNewBook(bookName) {
    this.setState({
      books: [...this.state.books, {name: bookName}],
    });
  }
}

{
  window.mountApp = element => {
    const root = ReactDOM.createRoot(element);
    root.render(e(App, null, null));
    return root;
  };
  window.mountApp(document.getElementById('root'));
  window.mountNestedApp = () => wind