bloc_subject 0.4.0

Reactive event based state management. Implementation of the Bloc pattern as an rxdart subject (BlocSubject).

example/main.dart

import 'package:bloc_subject/bloc_subject.dart';

sealed class AlphabetState {
  final int id;

  AlphabetState(this.id);
}

class A extends AlphabetState {
  A(super.id);
}

class B extends AlphabetState {
  B(super.id);
}

class C extends AlphabetState {
  C(super.id);
}

sealed class AlphabetEvent {}

class X implements AlphabetEvent {}

class Y implements AlphabetEvent {}

class Z implements AlphabetEvent {}

void main() async {
  int emitCount = 0;
  BlocSubject<AlphabetEvent, AlphabetState> subject =
      BlocSubject.seeded(A(emitCount),
          handler: (event, state) => switch (event) {
                X() => A(++emitCount),
                Y() => B(++emitCount),
                Z() => null,
              });
  final transformedStream = subject.stream
      .map((value) => switch (value) {
            A() => "A${value.id}",
            B() => "B${value.id}",
            C() => "C${value.id}",
          })
      .distinct();

  assert(subject.value is A);
  assert(await transformedStream.first == "A0");

  subject.addEvent(Y()); // Can process events and emit new states
  await Future.delayed(const Duration(milliseconds: 100));
  assert(subject.value is B);
  assert(await transformedStream.first == "B1");

  subject.addEvent(
      Z()); // If null is emitted from the handler, the state does not change/emit
  await Future.delayed(const Duration(milliseconds: 100));
  assert(subject.value is B);
  assert(await transformedStream.first == "B1");

  subject.add(C(1000)); // Still works like a regular `BehaviorSubject`
  assert(subject.value is C);
  assert(await transformedStream.first == "C1000");
}