GetX Binding Scope

pub package License: MIT

Scoped dependency injection for GetX — automatic cleanup, async safety, and nested bindings made easy.

Overview

A lightweight package offering scoped dependency injection using GetX-style Bindings, but decoupled from GetPage. Register dependencies with DI, wrap widgets in BindingScope, and your dependencies are cleaned up automatically—no more lifecycle headaches.

Perfect for Flutter apps that want the power of GetX dependency injection without being locked into GetX navigation.

✨ Key Features

  • 🗂 Scoped DI: Dependencies live only within their widget scope
  • 🧹 Automatic Cleanup: Only deletes what a scope created - no memory leaks
  • ⏳ Async Safe: First-registrant-wins behavior, handling putAsync races gracefully
  • 🔄 Reverse-Order Teardown: Maintains dependency integrity during cleanup
  • 🏗️ Nested Scopes: Prevents ownership bleed between nested bindings
  • 🚀 Router-Agnostic: Works with go_router, auto_route, Navigator 2.0, or any routing solution
  • 🎯 Zero Configuration: Drop-in replacement for GetX bindings with zero setup

📦 Installation

Add this to your package's pubspec.yaml file:

dependencies:
  getx_binding_scope: ^1.0.0
  get: ^4.7.2

Then run:

flutter pub get

🚀 Quick Start

1. Define a Binding with DI

import 'package:getx_binding_scope/getx_binding_scope.dart';
import 'package:get/get.dart';

class HomeBinding extends Bindings {
  @override
  void dependencies() {
    // Immediate registration
    DI.put<Config>(Config());
    
    // Lazy registration (created when first accessed)
    DI.lazyPut<ApiService>(() => ApiService(DI.find<Config>()));
    
    // Async registration with automatic race condition handling
    DI.putAsync<UserSession>(() async {
      final token = await AuthService.fetchToken();
      return UserSession(token);
    });
    
    // Factory registration (new instance each time)
    DI.create<Logger>(() => Logger('${DateTime.now()}'));
  }
}

2. Wrap Your Widget in BindingScope

import 'package:flutter/material.dart';
import 'package:getx_binding_scope/getx_binding_scope.dart';

class HomePage extends StatelessWidget {
  const HomePage({super.key});

  @override
  Widget build(BuildContext context) {
    return BindingScope(
      binding: HomeBinding(),
      child: Scaffold(
        appBar: AppBar(title: const Text('Home')),
        body: const HomeContent(),
      ),
    );
  }
}

class HomeContent extends StatelessWidget {
  const HomeContent({super.key});

  @override
  Widget build(BuildContext context) {
    // Access dependencies anywhere in the widget tree
    final apiService = DI.find<ApiService>();
    final config = DI.find<Config>();
    
    return Column(
      children: [
        Text('API Base URL: ${config.baseUrl}'),
        FutureBuilder<List<User>>(
          future: apiService.getUsers(),
          builder: (context, snapshot) {
            if (snapshot.hasData) {
              return ListView.builder(
                shrinkWrap: true,
                itemCount: snapshot.data!.length,
                itemBuilder: (context, index) {
                  return ListTile(
                    title: Text(snapshot.data![index].name),
                  );
                },
              );
            }
            return const CircularProgressIndicator();
          },
        ),
      ],
    );
  }
}

🔄 Advanced Usage

Nested Scopes

BindingScope supports nesting without ownership conflicts:

class ParentPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return BindingScope(
      binding: ParentBinding(), // Creates ParentService
      child: Column(
        children: [
          Text('Parent: ${DI.find<ParentService>().name}'),
          ChildWidget(), // Has its own scope
        ],
      ),
    );
  }
}

class ChildWidget extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return BindingScope(
      binding: ChildBinding(), // Creates ChildService
      child: Column(
        children: [
          Text('Parent: ${DI.find<ParentService>().name}'), // Still accessible
          Text('Child: ${DI.find<ChildService>().name}'),   // Only in this scope
        ],
      ),
    );
  }
}

Working with Different Routers

With GoRouter

final router = GoRouter(
  routes: [
    GoRoute(
      path: '/home',
      builder: (context, state) => BindingScope(
        binding: HomeBinding(),
        child: const HomePage(),
      ),
    ),
    GoRoute(
      path: '/profile',
      builder: (context, state) => BindingScope(
        binding: ProfileBinding(),
        child: const ProfilePage(),
      ),
    ),
  ],
);

With AutoRoute

@AutoRouteConfig()
class AppRouter extends _$AppRouter {
  @override
  List<AutoRoute> get routes => [
    AutoRoute(
      page: HomeWrapperRoute.page,
      path: '/home',
    ),
  ];
}

@RoutePage()
class HomeWrapperPage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return BindingScope(
      binding: HomeBinding(),
      child: const HomePage(),
    );
  }
}

Async Dependencies Best Practices

class AsyncBinding extends Bindings {
  @override
  void dependencies() {
    // Configure services that will be needed
    DI.put<Config>(Config());
    
    // Start async operations early
    DI.putAsync<DatabaseService>(() async {
      final db = DatabaseService();
      await db.initialize();
      return db;
    });
    
    // Dependent async services work correctly
    DI.putAsync<UserRepository>(() async {
      final db = await DI.find<DatabaseService>(); // Waits if still loading
      return UserRepository(db);
    });
  }
}

📋 Migration from GetX

Switching from GetX Bindings? Here's how to update:

Before (GetX) After (getx_binding_scope)
Get.put() DI.put()
Get.lazyPut() DI.lazyPut()
Get.putAsync() DI.putAsync()
Get.create() DI.create()
Get.find() DI.find()
GetPage(binding: ...) BindingScope(binding: ...)

Migration Example

// Before - GetX with routing
GetPage(
  name: '/home',
  page: () => HomePage(),
  binding: HomeBinding(),
)

// After - BindingScope (router agnostic)
BindingScope(
  binding: HomeBinding(),
  child: HomePage(),
)

⚠️ Important Notes

Lifecycle Management

  • Automatic Cleanup: Dependencies are automatically disposed when BindingScope is removed from the widget tree
  • Reverse Order: Dependencies are disposed in reverse creation order, ensuring proper cleanup
  • Async Safety: Async dependencies that finish after scope disposal are still cleaned up properly

Best Practices

  1. One Binding Per Feature: Create separate bindings for different features/pages
  2. Dependency Hierarchy: Place shared dependencies in parent scopes
  3. Avoid Global State: Use scoped dependencies instead of global singletons when possible
  4. Testing: Mock dependencies by creating test-specific bindings

Performance Considerations

  • Lazy Loading: Use DI.lazyPut() for expensive objects that might not be used immediately
  • Memory Efficiency: Scoped cleanup prevents memory leaks from accumulated dependencies
  • Async Handling: First-registrant-wins prevents duplicate async operations

🧪 Testing

class TestBinding extends Bindings {
  @override
  void dependencies() {
    DI.put<ApiService>(MockApiService()); // Use mocks in tests
    DI.put<UserRepository>(MockUserRepository());
  }
}

testWidgets('HomePage displays user data', (tester) async {
  await tester.pumpWidget(
    MaterialApp(
      home: BindingScope(
        binding: TestBinding(),
        child: HomePage(),
      ),
    ),
  );
  
  // Test your widget with mocked dependencies
  expect(find.text('Mock User Name'), findsOneWidget);
});

📚 API Reference

DI Class

  • DI.put<T>(T instance) - Register an immediate instance
  • DI.lazyPut<T>(T Function() builder) - Register a lazy factory
  • DI.putAsync<T>(Future<T> Function() builder) - Register an async instance
  • DI.create<T>(T Function() builder) - Register a factory (new instance each find)
  • DI.find<T>() - Retrieve a registered instance
  • DI.isRegistered<T>() - Check if a type is registered

BindingScope Widget

BindingScope({
  Key? key,
  required Bindings binding,
  required Widget child,
})
  • binding: The GetX binding to execute
  • child: The widget subtree that will have access to the dependencies

🤝 Contributing

Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.

📄 License

This project is licensed under the MIT License - see the LICENSE file for details.

Built with ❤️ for the Flutter community

Libraries

getx_binding_scope