bloc_arch_flow 1.0.3

A Bloc extension package to easily implement TCA or MVI architecture with Bloc using fpdart.

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Bloc Architecture Flow (bloc_arch_flow)

bloc_arch_flow is a Dart package that extends Flutter's BLoC (Business Logic Component) pattern by integrating predictable architectural patterns like MVI (Model-View-Intent) or TCA (The Composable Architecture). This package helps structure state management logic and makes it easier to test.

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🚀 Key Features

1. MVI (Model-View-Intent) Pattern Support

The BlocArchMvi abstract class helps you manage one-off side effects (Effects) separately from the state. For example, you can handle UI actions like showing a snackbar or navigating to a new screen independently of state changes, which clearly separates UI and business logic.

• mviEffects: A stream for the UI to subscribe to and process side effects.
• mviEmitEffect: A method to emit a side effect through the mviEffects stream.
• mviPerformTaskEither: A utility that uses fpdart's TaskEither to handle the success and failure of asynchronous operations in a clean, functional way.

2. TCA (The Composable Architecture) Pattern Support

The BlocArchTca abstract class enables a purely functional reducer-based architecture. All business logic is defined within the reducer, which creates a predictable and easily testable state flow.

• tcaReducer: A pure function that processes an action and returns a new state and a side effect.
• tcaPerformEffect: A utility that uses TaskEither to execute an asynchronous side effect and re-injects the result back into the system as a new action.

3. Automated Testing (BlocTestSuite)

BlocTestSuite is an abstract class for BLoC/Cubit testing. It automates test environment setups like setUp and tearDown, making your test code more concise and reusable.

• initTestSuite(): Automatically performs test suite initialization and cleanup tasks.
• blocArchTest(): A wrapper for bloc_test that simplifies test environment setup.

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📦 Installation

Add the following dependencies to your pubspec.yaml file.

dependencies:
  freezed_annotation: ^3.1.0
  fpdart: ^1.1.1
  flutter_bloc: ^9.1.1
  bloc: ^9.0.0
  bloc_arch_flow: ^1.0.3

dev_dependencies:
  flutter_test:
    sdk: flutter

  freezed: ^3.2.0
  build_runner: ^2.6.0
  bloc_test: ^10.0.0
  mocktail: ^1.0.4

📖 Usage

MVI (Model-View-Intent)

// MVI pattern applied to a BLoC example
class CounterMviBloc extends BlocArchMvi<CounterIntent, CounterState, CounterEffect> {
  CounterMviBloc(super.initialState);

  @override
  Future<void> mviHandleIntent(CounterIntent intent, Emitter<CounterState> stateEmitter) {
    // Implement intent handling logic here
  }
}

TCA (The Composable Architecture)

// TCA pattern applied to a BLoC example
class CounterTcaBloc extends BlocArchTca<CounterActions, CounterState, CounterEnvironment> {
  CounterTcaBloc(super.initialState, super.environment);

  @override
  ReducerEffect<CounterState, CounterActions> tcaReducer(
    CounterActions action,
    CounterState currentState,
    CounterEnvironment environment,
  ) {
    // Implement reducer logic here
    return (newState: currentState, effect: TaskEither.right(CounterActions.none()));
  }
}

Test Suite

// Test code using BlocTestSuite
class CounterMviBlocTestSuite
    extends BlocTestSuite<CounterMviBloc, CounterState, CounterIntent, CounterEnvironment> {
  @override
  CounterMviBloc buildBloc(CounterEnvironment environment) => CounterMviBloc(environment);

  @override
  CounterEnvironment buildEnvironment() => MockCounterEnvironment();
}

void main() {
  final testSuite = CounterMviBlocTestSuite();

  group('CounterMviBloc', () {
    testSuite.initTestSuite();

    testSuite.blocArchTest(
      'incrementAsync success should update count and set isLoading to false',
      // ... test logic
    );
  });
}