SetupWidget<T extends SetupWidget<T>> class abstract

A widget that uses a composition-based API similar to Vue's Composition API.

The setup function executes only once when the widget is first created, not on every rebuild. This provides better performance and a more predictable execution model compared to React-style hooks.

Hot Reload Behavior

During hot reload, hooks are matched in order by their runtime type:

• If types match in sequence, existing hooks are reused and SetupHook.reassemble is called
• If a type mismatch occurs, all subsequent hooks are unmounted in reverse order
• New or replacement hooks will have SetupHook.mount called

This ensures hooks maintain correct state during development while adapting to code changes.

Example:

class CounterWidget extends SetupWidget {
  const CounterWidget({super.key});

  @override
  setup(context, props) {
    final count = useSignal(0);

    return () => Column(
      children: [
        Text('Count: ${count.value}'),
        ElevatedButton(
          onPressed: () => count.value++,
          child: Text('Increment'),
        ),
      ],
    );
  }
}