Redux Simple

Simple Stupid Redux Store using Reactive Extensions

Redux Simple is a .NET library based on Redux principle. Redux Simple is written with Rx.NET and built with the minimum of code you need to scale your whatever .NET application you want to design.

Getting started

Like the original Redux library, you will have to initialize a new State when creating a Store + you will create Reduce functions each linked to an Action which will possibly update this State.

In your app, you can:

• Dispatch new Action to change the State
• and listen to events/changes using the Subscribe method

We will go through using an example.

The default State

Each State should immutable. That's why we prefer to use immutable types for each property of the State.

public class AppState
{
    public string CurrentPage { get; set; } = string.Empty;
    public ImmutableArray<string> Pages { get; set; } = ImmutableArray<string>.Empty;
}

A simple Store

You will need 3 steps to create your own Redux Store:

1. Create Actions used in the Reduce function

public class NavigateAction
{
    public string PageName { get; set; }
}

public class GoBackAction { }

public class ResetAction { }

2. Create a new Store class inherited from ReduxStore

public sealed class MyAppStore : ReduxStore<AppState>
{
    public override AppState Reduce(AppState state, object action)
    {
        switch (action)
        {
            case NavigateAction navigateAction:
                return Reduce(state, navigateAction);
            case GoBackAction goBackAction:
                return Reduce(state, goBackAction);
            case ResetAction resetAction:
                return Reduce(state, resetAction);
        }

        return base.Reduce(state, action);
    }

    private static AppState Reduce(AppState state, NavigateAction action)
    {
        return new AppState
        {
            CurrentPage = action.PageName,
            Pages = state.Pages.Add(action.PageName)
        };
    }
    private static AppState Reduce(AppState state, GoBackAction action)
    {
        var newPages = state.Pages.RemoveAt(state.Pages.Length - 1);

        return new AppState
        {
            CurrentPage = newPages.LastOrDefault(),
            Pages = newPages
        };
    }
    private static AppState Reduce(AppState state, ResetAction action)
    {
        return new AppState
        {
            CurrentPage = string.Empty,
            Pages = ImmutableArray<string>.Empty
        };
    }
}

3. Create a new instance of your Store

sealed partial class App
{
    public static readonly MyAppStore Store;

    static App()
    {
        Store = new MyAppStore();
    }
}

Dispatch & Subscribe

You can now dispatch new actions using your globally accessible Store.

using static MyApp.App; // static reference on top of your file

Store.Dispatch(new NavigateAction { PageName = "Page1" });
Store.Dispatch(new NavigateAction { PageName = "Page2" });
Store.Dispatch(new GoBackAction());

And subscribe to either state changes or actions raised.

using static MyApp.App; // static reference on top of your file

Store.ObserveAction<NavigateAction>().Subscribe(_ =>
{
    // TODO : Handle navigation
});

Store.ObserveState()
    .Where(state => state.CurrentPage == nameof(Page1))
    .Subscribe(_ =>
    {
        // TODO : Handle event when the current page is now "Page1"
    });

Asynchronous Actions

When you work with asynchronous tasks (side effects), you can follow the following rule:

• Create 3 actions - a normal/start action, a fulfilled action and a failed action
• Reduce/Handle response on fulfilled action
• Reduce/Handle error on failed action

Here is a concrete example.

List of actions

public class GetTodosAction { }
public class GetTodosFulfilledAction
{
    public ImmutableArray<Todo> Todos { get; set; }
}
public class GetTodosFailedAction
{
    public int StatusCode { get; set; }
    public string Reason { get; set; }
}

Store.Dispatch(new GetTodosAction());

Reduce functions

private static AppState Reduce(AppState state, GetTodosAction action)
{
    return new AppState
    {
        Loading = true,
        Todos = state.Todos
    };
}
private static AppState Reduce(AppState state, GetTodosFulfilledAction action)
{
    return new AppState
    {
        Loading = false,
        Todos = action.Todos.ToImmutableArray()
    };
}
private static AppState Reduce(AppState state, GetTodosFailedAction action)
{
    return new AppState
    {
        Loading = false,
        Todos = ImmutableArray<Todo>.Empty
    };
}

Contributors

mhusainisurge

• Observe partial state #7
• ReduxStoreWithHistory #9