Rivertion #

Rivertion is a Flutter state management library that bridges the gap between traditional state holders (like ValueNotifier, ChangeNotifier, and Bloc) and a modern, reactive consumption model inspired by Riverpod.

Instantly convert any Listenable or BlocBase into a Source and consume it in your widgets without the boilerplate of multiple Builder widgets or manual listener management.

Key Feature: A Unified Consumption Model #

Tired of juggling BlocBuilder, ValueListenableBuilder, and manual addListener boilerplate? Rivertion simplifies this by converting your existing state holders into a unified Source type, which can be consumed consistently in your UI.

From ValueNotifier to Source #

Before: The old way

ValueListenableBuilder(
  valueListenable: counterNotifier,
  builder: (context, count, _) {
    return Text('Count: $count');
  }
)

After: The Rivertion way

SourceBuilder(
  builder: (context, scope, _) {
    // Rebuilds automatically when the notifier changes
    final count = scope.watch(counterNotifier.source);
    return Text('Count: $count');
  },
)

From Bloc / Cubit to Source #

Before: The old way

BlocBuilder<CounterCubit, int>(
  bloc: counterCubit,
  builder: (context, count) {
    return Text('Count: $count');
  }
)

After: The Rivertion way

SourceBuilder(
  builder: (context, scope, _) {
    // The .source extension comes from the generated file
    final count = scope.watch(counterCubit.source);
    return Text('Count: $count');
  },
)

You get a single, consistent way (scope.watch) to listen to any state source.

Core Concepts #

SourceWidget & SourceScope #

SourceWidget (and its simpler version SourceBuilder) is a StatefulWidget that provides a SourceScope in its build method. The scope is the key to interacting with your sources.

• scope.watch(source): Subscribes a widget to a Source. The widget will rebuild whenever the source's value changes. This is the most common method you'll use.
• scope.listen(source, (previous, next) { ... }): Subscribes to a Source to perform actions in response to state changes, like showing a SnackBar or navigating. It does not cause the widget to rebuild.

Standalone State: SourceController #

For state that doesn't need to be shared with other state management systems, or for simple, local widget state, Rivertion provides SourceController. It works just like a ValueNotifier but is integrated directly into the Rivertion ecosystem.

final counterProvider = SourceController(0);

// Watch it in the UI
final count = scope.watch(counterProvider.source);

// Update it
counterProvider.state++;

Code Generation for Interoperability #

Rivertion also includes a command-line tool to generate support files for other popular packages, enhancing interoperability.

Run the tool with the following command:

dart run rivertion --packages <package_name> --output <output_path>

• --packages: A comma-separated list of packages. Currently supports bloc, riverpod and reactive_forms.
• --output: The path to the output folder for the generated files.

Example #

dart run rivertion --packages bloc,riverpod,reactive_forms --output lib/generated

This will create:

• lib/generated/bloc_sources.dart
• lib/generated/source_consumer_widgets.dart
• lib/generated/reactive_form_sources.dart

Bloc and Cubit Support #

The bloc_sources.dart file provides a .source extension on BlocBase, instantly converting any Bloc or Cubit into a Source that can be consumed by SourceBuilder.

Riverpod Interoperability #

The source_consumer_widgets.dart file provides SourceConsumerWidget to seamlessly use Riverpod providers within a SourceWidget, allowing you to mix and match both systems.

Reactive Forms Support #

The reactive_form_sources.dart file provides extensions to easily bind Sources to reactive_forms controls, keeping your form state perfectly in sync with your application's state.