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A Dart package that helps implement the BLoC pattern in AngularDart. Built to work with package:bloc.

Learn more at bloclibrary.dev!

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Angular Components

BlocPipe is an Angular pipe which helps bind Bloc state changes to the presentation layer. BlocPipe handles rendering the html element in response to new states. BlocPipe is very similar to AsyncPipe but is designed specifically for blocs.

Cubit Usage

Lets take a look at how to use BlocPipe to hook up a CounterPage html template to a CounterCubit.

counter_cubit.dart

import 'package:bloc/bloc.dart';

class CounterCubit extends Cubit<int> {
  CounterCubit() : super(0);

  void increment() => emit(state + 1);
  void decrement() => emit(state — 1);
}

counter_page_component.dart

import 'package:angular/angular.dart';
import 'package:angular_bloc/angular_bloc.dart';

import './counter_cubit.dart';

@Component(
  selector: 'counter-page',
  templateUrl: 'counter_page_component.html',
  pipes: [BlocPipe],
)
class CounterPageComponent implements OnInit, OnDestroy {
  late final CounterCubit counterCubit;

  @override
  void ngOnInit() {
    counterCubit = CounterCubit();
  }

  @override
  void ngOnDestroy() {
    counterCubit.close();
  }
}

counter_page_component.html

<div>
  <h1>Counter App</h1>
  <h2>Current Count: {{ $pipe.bloc(counterCubit) }}</h2>
  <button (click)="counterCubit.increment()">➕</button>
  <button (click)="counterCubit.decrement()">➖</button>
</div>

Bloc Usage

Lets take a look at how to use BlocPipe to hook up a CounterPage html template to a CounterBloc.

counter_bloc.dart

import 'package:bloc/bloc.dart';

sealed class CounterEvent {}
final class CounterIncrementPressed extends CounterEvent {}
final class CounterDecrementPressed extends CounterEvent {}

class CounterBloc extends Bloc<CounterEvent, int> {
  CounterBloc() : super(0) {
    on<CounterIncrementPressed>((event, emit) => emit(state + 1));
    on<CounterDecrementPressed>((event, emit) => emit(state - 1));
  }
}

counter_page_component.dart

import 'package:angular/angular.dart';
import 'package:angular_bloc/angular_bloc.dart';

import './counter_bloc.dart';

@Component(
  selector: 'counter-page',
  templateUrl: 'counter_page_component.html',
  pipes: [BlocPipe],
)
class CounterPageComponent implements OnInit, OnDestroy {
  late final CounterBloc counterBloc;

  @override
  void ngOnInit() {
    counterBloc = CounterBloc();
  }

  @override
  void ngOnDestroy() {
    counterBloc.close();
  }

  void increment() => counterBloc.add(CounterIncrementPressed());

  void decrement() => counterBloc.add(CounterDecrementPressed());
}

counter_page_component.html

<div>
  <h1>Counter App</h1>
  <h2>Current Count: {{ $pipe.bloc(counterBloc) }}</h2>
  <button (click)="increment()">+</button>
  <button (click)="decrement()">-</button>
</div>

At this point we have successfully separated our presentational layer from our business logic layer!

Dart Versions

• Dart 2: >= 2.12.0

Examples

• Counter - a complete example of how to create a CounterBloc and hook it up to an AngularDart app.
• Github Search - an example of how to create a Github Search Application using the bloc and angular_bloc packages.

Maintainers

• Felix Angelov