using System;

using Iso8601DurationHelper;

using System.Text.Json;

using Newtonsoft.Json;

​

public class Program

{

    class type { public string a { get; set; } }

    public static void Main()

    {

        var systemTextJsonOptions = new System.Text.Json.JsonSerializerOptions(System.Text.Json.JsonSerializerDefaults.Web);

        var emptyValue = new { a = (string)"" };

        var nullValue = new { a = (string)null};

        var withValue = new { a = (string)"a" };

​

        Console.WriteLine("With value:");

        Console.WriteLine("System.Text.Json: " + System.Text.Json.JsonSerializer.Serialize(withValue, systemTextJsonOptions));

        Console.WriteLine("Newtonsoft.Json: " + Newtonsoft.Json.JsonConvert.SerializeObject(withValue));

        Console.WriteLine();

        Console.WriteLine("Empty value:");

        Console.WriteLine("System.Text.Json: " + System.Text.Json.JsonSerializer.Serialize(emptyValue, systemTextJsonOptions));

        Console.WriteLine("Newtonsoft.Json: " + Newtonsoft.Json.JsonConvert.SerializeObject(emptyValue));

        Console.WriteLine();

        Console.WriteLine("Null value:");

        Console.WriteLine("System.Text.Json: " + System.Text.Json.JsonSerializer.Serialize(nullValue, systemTextJsonOptions));

        Console.WriteLine("Newtonsoft.Json: " + Newtonsoft.Json.JsonConvert.SerializeObject(nullValue));

        Console.WriteLine();

        var emptyValueJson = "{ \"a\": \"\" }";

        var nullValueJson = "{ \"a\": null }";

        var withValueJson = "{ \"a\": \"a\" }";

        Console.WriteLine("With value json:");

        Console.WriteLine("System.Text.Json: " + (System.Text.Json.JsonSerializer.Deserialize<type>(withValueJson).a ?? "null"));

        Console.WriteLine("Newtonsoft.Json: " + (Newtonsoft.Json.JsonConvert.DeserializeObject<type>(withValueJson).a ?? "null"));

        Console.WriteLine();

        Console.WriteLine("Empty value json:");

        Console.WriteLine("System.Text.Json: " + (System.Text.Json.JsonSerializer.Deserialize<type>(emptyValueJson).a ?? "null"));

        Console.WriteLine("Newtonsoft.Json: " + (Newtonsoft.Json.JsonConvert.DeserializeObject<type>(emptyValueJson).a ?? "null"));

        Console.WriteLine();

        Console.WriteLine("Null value json:");

        Console.WriteLine("System.Text.Json: " + (System.Text.Json.JsonSerializer.Deserialize<type>(nullValueJson).a ?? "null"));

        Console.WriteLine("Newtonsoft.Json: " + (Newtonsoft.Json.JsonConvert.DeserializeObject<type>(nullValueJson).a ?? "null"));

        Console.WriteLine();

​

    }

}