Umbraco-CMS/src/Umbraco.Web.Common/Extensions/ActionResultExtensions.cs

using System.Net;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Infrastructure;

namespace Umbraco.Extensions
{
    public static class ActionResultExtensions
    {
        public static bool IsSuccessStatusCode(this ActionResult actionResult)
        {
            var statusCode = actionResult switch
            {
                IStatusCodeActionResult x => x.StatusCode,
                _ => (int?)null
            };

            return statusCode.HasValue && statusCode.Value >= (int)HttpStatusCode.OK && statusCode.Value < (int) HttpStatusCode.Ambiguous;
        }
    }
}