Dart: Debouncer

debouncer.dart

import 'dart:async';
// Creditos
// https://stackoverflow.com/a/52922130/7834829

class Debouncer<T> {

  Debouncer({ this.duration, this.onValue });

  final Duration duration;
  void Function(T value) onValue;
  T _value;
  Timer _timer;
  
  T get value => _value;

  set value(T val) {
    _value = val;
    _timer?.cancel();
    _timer = Timer(duration, () => onValue(_value));
  }  
}

uso_debouncer.dart

// final debouncer = Debouncer<String>(duration: Duration(milliseconds: 500 ));

void getSugerenciasPorQuery( String busqueda, LatLng proximidad ) {

  debouncer.value = '';
  debouncer.onValue = ( value ) async {
    final resultados = await this.getResultadosPorQuery(value, proximidad);
    this._sugerenciasStreamController.add(resultados);
  };

  final timer = Timer.periodic(Duration(milliseconds: 200), (_) {
    debouncer.value = busqueda;
  });

  Future.delayed(Duration(milliseconds: 201)).then((_) => timer.cancel()); 

}