SimpleWebChat/SimpleWebChat.BlazorWasm/Program.cs

using Microsoft.AspNetCore.Components.Web;
using Microsoft.AspNetCore.Components.WebAssembly.Hosting;
using SimpleWebChat.BlazorWasm;

var builder = WebAssemblyHostBuilder.CreateDefault(args);
builder.RootComponents.Add<App>("#app");
builder.RootComponents.Add<HeadOutlet>("head::after");

builder.Services.AddScoped(sp =>
{
    var http = new HttpClient();

#if DEBUG
    http.BaseAddress = new Uri("http://swc-server");
#else
    var NavManager = sp.GetService<Microsoft.AspNetCore.Components.NavigationManager>();
    var ba = new Uri($"{NavManager.ToAbsoluteUri("/").GetLeftPart(UriPartial.Scheme | UriPartial.Authority)}");
    http.BaseAddress = ba;
#endif

    return http;
});

await builder.Build().RunAsync();