how to implement debouncer for events with 'onEvent'?

user_9455518 0
Viewed 864

transformEvents method will be removed in bloc version 8, and we should use onEvent method instead of, how can we implement debounce for events with onEvent?

  @override
  Stream<Transition<PriceProposalEvent, PriceProposalState>> transformEvents(
    Stream<PriceProposalEvent> events,
    TransitionFunction<PriceProposalEvent, PriceProposalState> transitionFn,
  ) =>
      super.transformEvents(
        events.debounceTime(const Duration(milliseconds: 200)),
        transitionFn,
      );
flutter-bloc bloc dart flutter
2 Answers

New in Bloc 7.2.0 https://verygood.ventures/blog/whats-new-in-bloc-v7-2-0

Now it uses transformer!

import 'package:bloc/bloc.dart';
import 'package:stream_transform/stream_transform.dart';

class YourBloc extends Bloc<Event, State> {
  YourBloc() : super(StateInitial()) {

    on<PriceProposalEvent>(_onPriceProposalEvent,
        transformer: debounce(const Duration(milliseconds: 200)));
  }
}
//Debounce query requests
EventTransformer<E> debounce<E>(Duration duration) {
  return (events, mapper) {
    return events.debounce(duration).switchMap(mapper);
  };
}

Hope, it may help ya!

user_91402530

using the rxdart library for the stream methods that I see you're already using:

static Stream<T> debounce<T>(
    Stream<T> events,
    Stream<T> Function(T) transitionFn,
) {
    return events
        .debounceTime(const Duration(milliseconds: 200))
        .switchMap(transitionFn);
}
user_103556440
Related