ASP.NET JavaScriptServices v2 Template - Add Azure B2C Authentication Static Files

Question

I'm using the new ASP.NET JavaScriptServices template and trying to add basic B2C authentication.

I simply want if the user doesn't have an ASP.NET Core Auth Cookie for them to be directed instantly to login to B2C.

I feel I'm close in attempting to force Challenge, but it keeps redirecting back and never actually feeding me to a login page. This is using localhost.

Full code sample can be found here:

https://github.com/aherrick/AToMS.Config.Web

What do I need to change in order to force auth on initial request?

Below is the Startup Configure method in question:

    public void Configure(IApplicationBuilder app, IHostingEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }
        else
        {
            app.UseExceptionHandler("/Home/Error");
        }

        app.UseStaticFiles();
        app.UseSpaStaticFiles();

        app.UseAuthentication();

        app.Use(async (context, next) =>
        {
            if (!context.User.Identity.IsAuthenticated)
            {
                // force login here? but it keeps redirecting back infinite loop.

                await context.ChallengeAsync(OpenIdConnectDefaults.AuthenticationScheme);
                return;
            }
            await next.Invoke();
        });

        app.UseMvc(routes =>
        {
            routes.MapRoute(
                name: "default",
                template: "{controller}/{action=Index}/{id?}");
        });

        app.UseSpa(spa =>
        {
            // To learn more about options for serving an Angular SPA from ASP.NET Core,
            // see https://go.microsoft.com/fwlink/?linkid=864501
            spa.Options.SourcePath = "ClientApp";

            if (env.IsDevelopment())
            {
                spa.UseAngularCliServer(npmScript: "start");
            }
        });
    }


    public void ConfigureServices(IServiceCollection services)
    {
        services.AddAuthentication(sharedOptions =>
         {
             sharedOptions.DefaultScheme = CookieAuthenticationDefaults.AuthenticationScheme;
             sharedOptions.DefaultChallengeScheme = OpenIdConnectDefaults.AuthenticationScheme;
         })
    .AddAzureAdB2C(options => Configuration.Bind("AzureAdB2C", options))
    .AddCookie(configureOptions =>
    {
    });

        services.AddMvc();

        // In production, the Angular files will be served from this directory
        services.AddSpaStaticFiles(configuration =>
        {
            configuration.RootPath = "ClientApp/dist";
        });
    }