BadFL Example Code (helper/debounce)

main.dart

import 'dart:async';

class BadDebouncer {
  final Duration delay;

  /// default action to be called when the debouncer is called without a action
  final void Function()? defaultAction;

  Timer? _timer;

  BadDebouncer({this.delay = const Duration(seconds: 1), this.defaultAction});

  void call([void Function()? action]) {
    assert(
      action != null || defaultAction != null,
      'can only call debouncer without action when defaultAction is provided',
    );

    _timer?.cancel();
    _timer = Timer(delay, (action ?? defaultAction)!);
  }

  /// cancel the current delayed call
  void cancel() => _timer?.cancel();
}

void main() async {
  final debouncer = BadDebouncer(
    delay: const Duration(seconds: 1),
    defaultAction: () {
      print('default action');
    },
  );

  // 1. call the default action
  debouncer();

  // 2. call with a custom action
  await Future.delayed(const Duration(seconds: 2));
  debouncer.call(() {
    print('wrong action');
  });

  // 3. cancel the current delayed call
  debouncer.cancel();
  debouncer(() {
    print('correct action');
  });
}

// Output:
// default action
// correct action