why .net-core react template is not typed

I am new in application development rea, I just created a new application with Visual Studio 2017 Enterprise Edition, everything is fine, but the reactive part is in javascript format (.js) and not in script-script type ( .jsx), I read some tutorials but when they create a reaction application, they are all script type! Is there anything else I have to do?
Here is an example of these tutorials: https://social.technet.microsoft.com/wiki/contents/articles/51632.asp-net-core-2-0-crud-with-react-js-and-entity-framework -core.aspx