State<Counter> createState() => CounterState(); } class CounterState extends State<Counter> { int count = 0; @override Iterable<Component> build(BuildContext context) sync* { yield div( styles: Styles(textAlign: TextAlign.center, fontSize: Unit.em(5)), [ span([text('$count')]), button( onClick: () => setState(() => count++), [text('+1')], ), ]); } } MJCDPVOUFSEBSU