It appears that there is an issue building angular 5.0 applications using the angular cli when building or serving with AOT.
I have documented the issue in detail here:
https://github.com/ServiceStack/servicestack-client/issues/13
This is now resolved in the latest angular-cli template release which has been updated to use the latest Angular dependencies and includes registration of JsonServiceClient provider:
providers: [{provide:JsonServiceClient, useValue: new JsonServiceClient("/")}],
Which you can run dotnet-new again to create a new project with the latest template:
$ dotnet-new angular-cli ProjectName