For the moment almost all blog posts covering configuration with the new ASP.NET 5 and MVC 6 using json for config is using something like this:
var token = configuration.Get<string>("AppData:CompanyName");
For example this question: How to read AppSettings values from Config.json in ASP.NET Core
But since 6 august this function is removed (if you're using bleeding edge releases) with almost no information on what to use instead.
For me this first occurred when switching to from beta5
to beta6
of Microsoft.Framework.Configuration.Json
.