favour_state 0.0.2

State management for flutter

favour_state

State management solution for flutter inspired by cerebraljs and property_change_notifier

Documentation now in WIP status. Please look at example.

#Example

// state.dart

import 'package:favour_state/favour_state.dart';

class ExampleState implements StoreState<ExampleState> {
  final int counter;
  final bool enabled;

  int get controllableCounter => enabled ? counter : 0;

  const ExampleState({
    this.counter = 0,
    this.enabled = true,
  });

  @override
  ExampleState copyWith({
    int counter,
    bool enabled,
  }) {
    if ((counter == null || identical(counter, this.counter)) &&
        (enabled == null || identical(enabled, this.enabled))) {
      return this;
    }

    return ExampleState(
      counter: counter ?? this.counter,
      enabled: enabled ?? this.enabled,
    );
  }
}

// store.dart

import 'package:favour_state/favour_state.dart';

import 'state.dart';

class ExampleStore extends BaseStore<ExampleState> {
  // Any reaction is optional
  ValueReaction<ExampleState, bool> enabled;
  ValueReaction<ExampleState, int> controllableCounter;
  ValueReaction<ExampleState, ExampleState> self;

  EffectReaction<ExampleState> onCounterChange;

  // if you not declare reaction you can leave the method empty
  @override
  void initReactions() {
    // under the hood value reaction implement ValueListenable
    enabled = valueReaction((s) => s.enabled, topics: {#enabled});
    controllableCounter = valueReaction(
      (s) => s.controllableCounter,
      topics: {#enabled, #counter},
    );
    self = valueReaction((s) => s);

    // in closure of effect reaction you can use anything from class scope
    onCounterChange = effectReaction(
      // ignore: avoid_print
      (s) => print('counter changed'),
      topics: {#counter},
    );
  }

  // you can initialize your state
  @override
  ExampleState initState() => const ExampleState(counter: 1);

  Future<void> multiply(int multiplier) async {
    await run(MultiplyCounter(multiplier));
  }

  Future<void> toggle() async {
    await run(action<ExampleStore>((store, mutator, [services]) {
      // #name - should be equal to state copyWith named params
      // For example if copyWith is 'void copyWith({int counter, bool enabled})'
      // you can use #counter and #enabled to mutate state
      mutator[#enabled] = !store.state.enabled;
    }));
  }
}

// Action can be class based
class MultiplyCounter extends StoreAction<ExampleStore> {
  // constructor can declare positional and optional params
  MultiplyCounter(int multiplier)
      : super(
          // closure for action should declare this params
          (store, mutator, [services]) {
            // You can use any of this api to mutate state
            // mutator[#counter] = 1
            // mutator.changes = {#counter: 1, #enabled: false};
            // mutator.merge({#counter: 1, #enabled: false});
            // mutator.set(#counter, 1);
            mutator[#counter] = store.state.counter * multiplier;
          },
        );
}

// main.dart

import 'package:favour_state/favour_state.dart';
import 'package:flutter/material.dart';
import 'package:flutter/widgets.dart';
import 'package:get_it/get_it.dart';

import 'store.dart';

void bootstrapStores(AppState appState) {
  // Store initialized after registration
  // when method bootstrapServices called
  // Runtime setup into state and methods
  // initState and initReactions called

  // Store can be registered using this api
  // appState.registerStore(AnotherStore());
  // appState.registerDerivedStore(
  //   (store) => SomeStore(dependency: stores<AnotherStore>())
  // )
  // when you register derived store you can get already registered stores
  appState.registerStore(ExampleStore());
}

void main() {
  runApp(ExampleApp());
}

// ignore: use_key_in_widget_constructors
class ExampleApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) => MaterialApp(
        home: AppStateProvider(
          bootstrap: bootstrapStores,
          serviceProvider: GetIt.I,
          child: Builder(
            builder: (context) {
              final store = AppStateScope.store<ExampleStore>(context);
              // ignore: avoid_unnecessary_containers
              return Scaffold(
                body: Center(
                  child: Column(
                    mainAxisAlignment: MainAxisAlignment.center,
                    children: [
                      ValueListenableBuilder(
                          valueListenable: store.controllableCounter,
                          builder: (context, value, child) => Text('$value')),
                      RaisedButton(
                        onPressed: () => store.multiply(2),
                        child: const Text('Doubly'),
                      ),
                      RaisedButton(
                        onPressed: store.toggle,
                        child: const Text('Toggle'),
                      ),
                    ],
                  ),
                ),
              );
            },
          ),
        ),
      );
}

Introduction

Goals

ToDo

• core functionality
• basic tests
• more tests
• error handling
• logging
• dev tools
• improve documentation

State

A simple State can be declared as follows

import 'package:favour_state/favour_state.dart';

class ExampleState extends StoreState<ExampleState> {
  @override
  ExampleState copyWith() => ExampleState();
}

Any state used in the store must extend or implement StoreState<T> where T is the state type that extends or implements StoreState

Any state must implement the copyWith method. Since the state must be immutable, the copyWith method is the only way to partially change the state.

---

Store

A simple Store can be declared as follows

import 'package:favour_state/favour_state.dart';

import 'state.dart';

class ExampleStore extends BaseStore<ExampleState> {
  @override
  void initReactions() {}

  @override
  ExampleState initState() => ExampleState();
}

Any Store must extend BaseStore<T> where T is the state type that extend or implement StoreState and used with this Store.

Any Store must implement initReactions and initState methods. Method initState should return instance of state which conforms to T. Method initReactions could be empty.

Internals

Work in progress

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Reactions

Work in progress

Value Reaction

Work in progress

Effect Reaction

Work in progress

Internals

Work in progress

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Actions

Class-based action

Work in progress

Action from helper function

Work in progress

Internals

Work in progress

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AppState

Work in progress

Services provider

Work in progress

Store registration

Work in progress

Get store by type

Work in progress

Internals

Work in progress

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Widgets

Work in progress

AppStateProvider

Work in progress

AppStateScope

Work in progress

Internals

Work in progress

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Internals

Work in progress

StoreRuntime

Work in progress