What is this?
It's a template project for a SPA application on asp.net core using React.js and Redux written in ES2015 syntax. It's the same template as the one in original repository that is called ReacReduxSpa but it's developed in JavaScript rather than TypeScript.
What is JavaScript services?
JavaScriptServices is a set of technologies for ASP.NET Core developers. It provides infrastructure that you'll find useful if you use Angular 2 / React / Knockout / etc. on the client, or if you build your client-side resources using Webpack, or otherwise want to execute JavaScript on the server at runtime. Everything is cross-platform, and works with .NET Core 1.0 RC2 or later on Windows, Linux, or OS X.
Differences with the TypeScript version
There are small differences with the corresponding TypeScript version. Most importantly there is no yo generator for this template so far. So if you want to create an application based on this template you have to clone it locally and modify it according to your needs.
On top of that there is a slightly difference in the way the bundles are created during development and production. Initially there is no need to create explicitly the vendor bundle by executing the webpack command before launching the project. It's enough to just execute dotnet run and the library will take care creating the bundles. For production now you have to manually create the bundles and probably add them to source control as they are part of your application. In order to create these bundles you have to execute npm run dist from the root of the app. This could be also part of your build process. Once it's finished successfully there will be two JavaScript files one containing the code of yout application and the other one all the vendor code that doesn't change often, only when upgrading or adding new libraries. The generated files are located inside the wwwroot\dist folder.
For more information please visit the JavaScriptServices project