Stator

Stator is a simple, DI-oriented, Redux-inspired or Model-View-Update (MVU) experiment using C# 9.0. It works well with Blazor and MobileBlazorBindings, including sharing states between the Xamarin part and the Blazor part of a hybrid mobile app. It should also work with any other .NET stateful client model.

As of 2021-04-08, the project does not support .NET Standard 2.0, only .NET 5+

This project uses:

• C# 9 record classes to ensure immutability and to simplify reducers.
• Dependency Injection to manage states (and everything else)

How to install?

Name	NuGet.org	feedz.io
dotnet add package StateR
dotnet add package StateR.Blazor
dotnet add package StateR.Blazor.Experiments
dotnet add package StateR.Experiments

Counter sample

The following snippet represent a feature, surrounding a counter, where you can Increment, Decrement, and Set the value of the Count property of that Counter.State. The snippet also include the InitialState of that counter.

services
    .AddStateR(appAssembly)
    .AddAsyncOperations() // Add support for Redux thunk-like helpers
    .AddReduxDevTools() // Add support for Redux DevTools
    .Apply()
;

using StateR;

namespace BlazorMobileHybridExperiments.Features
{
    public class Counter
    {
        public record State(int Count) : StateBase;

        public class InitialState : IInitialState<State>
        {
            public State Value => new State(0);
        }

        public record Increment : IAction;
        public record Decrement : IAction;

        public class Reducers : IReducer<State, Increment>, IReducer<State, Decrement>
        {
            public State Reduce(State state, Increment action) => state with { Count = state.Count + 1 };
            public State Reduce(State state, Decrement action) => state with { Count = state.Count - 1 };
        }
    }
}

Then from a Blazor component that inherits from StatorComponent, we can dispatch those actions.

@page "/counter"
@inherits StateR.Blazor.StatorComponent
@inject IState<Features.Counter.State> CounterState

<h1>Counter</h1>
<p>Current count: @CounterState.Current.Count</p>
<button class="btn btn-primary" @onclick="@(async () => await DispatchAsync(new Features.Counter.Increment()))">+</button>
<button class="btn btn-primary" @onclick="@(async () => await DispatchAsync(new Features.Counter.Decrement()))">-</button>

It is not needed to inherit from StatorComponent, a component (or any class) can manually subscribe to any IState<T>.

The origin

I played around with a few other libraries and I was not 100% satisfied with how they did stuff. So while playing around with MobileBlazorBindings and the new hybrid apps, I found that C# 9 records were a great fit for this. I started experimenting with transforming immutable types (records) and ended up creating this project.

Origin of the name

The name StateR, pronounced Stator, is inspired by MediatR that was initially used under the hood to mediate the commands.

Definition of a Stator

The stator is the stationary part of a rotary system [...]. Energy flows through a stator to or from the rotating component of the system.

Source: wikipedia

Why Redux?

After hearing about it for years, I read about it and found the concept brilliant, experimented with it, and adopted the idea.

What is different in this library?

This library is based on the concepts introduced by Redux, but .NET is not JavaScript and .NET Core is built around Dependency Injection (DI), so I decided to take advantage of that.

There is no type and no real DI in JavaScript, so it make sense that the folks there did not take that into account when they built Redux.

Redux DevTools

I based the Redux DevTools implementation on Fluxor, which is a similar project, that I used once. That helped me lower the implementation time to connect Stator with Redux DevTools; thanks.

To be continued

...

Found a bug or have a feature request?

Please open an issue and be as clear as possible; see How to contribute? for more information.

How to contribute?

If you would like to contribute to the project, first, thank you for your interest, and please read Contributing to ForEvolve open source projects for more information.

Contributor Covenant Code of Conduct

Also, please read the Contributor Covenant Code of Conduct that applies to all ForEvolve repositories.

Test (my clipboard/notes)

Coverlet code coverage

• dotnet test /p:CollectCoverage=true => coverage.json

• dotnet test /p:CollectCoverage=true /p:CoverletOutputFormat=cobertura => coverage.cobertura.xml

• dotnet test --collect:"XPlat Code Coverage" => TestResults/{GUID}/coverage.cobertura.xml

• dotnet tool install -g dotnet-reportgenerator-globaltool

• reportgenerator -reports:coverage.cobertura.xml -targetdir:coveragereport -reporttypes:Html

dotnet test /p:CollectCoverage=true /p:CoverletOutputFormat=cobertura
reportgenerator "-reports:test\**\coverage.cobertura.xml" -targetdir:coveragereport -reporttypes:Html