Args2Json.cs

public static class Args2Json
{
  private static Dictionary<string, string> ApplyPair(this Dictionary<string, string> dict, string key,
    string value)
  {
    dict.Add(key, value);
    return dict;
  }

  private static Dictionary<string, string> ApplyAssignatoryPair(this Dictionary<string, string> dict,
    (string key, string value) tpl) =>
    dict.ApplyPair(tpl.key, tpl.value);

  private static ExpandoObject MapProperties<T>(Dictionary<string, string> pairs) =>
    GetPropertyNames<T>()
      .Aggregate(new ExpandoObject(), (o, p) => GetMappedArgValue(pairs, o, p));

  private static ExpandoObject GetMappedArgValue(Dictionary<string, string> pairs, ExpandoObject target,
    (string propertyName, string propertyNameTest) tpl)
  {
    ((IDictionary<string, Object>) target).Add(
      tpl.propertyName,
      pairs.TryGetValue(tpl.propertyNameTest, out string value) switch
      {
        true => value,
        _ => null
      }
    );
    return target;
  }

  private static (string, string) ParseEqualsArg(string arg, int splitIndex) =>
    (splitIndex, arg.Replace("-", "").AsMemory()) switch
    {
      (-1, _) => throw new Exception($"Invalid assignatory argument: ${arg}"),
      var (_, span) => (span.Slice(0, splitIndex -1).ToString().ToLowerInvariant(), span.Slice(splitIndex).ToString())
    };

  private static Dictionary<string, string> GetArgumentNamePairs(string[] args) =>
    args.Aggregate((new Dictionary<string, string>(), ""), ParseStreamArg).Item1;

  private static (Dictionary<string, string>, string) ParseStreamArg(
    (Dictionary<string, string> dict, string key) tpl, string arg) =>
    (tpl.key, arg.IndexOf('=')) switch
    {
      var (_, index) when index > -1 => (tpl.dict.ApplyAssignatoryPair(ParseEqualsArg(arg, index)), ""),
      ("", _) => (tpl.dict, arg.Replace("-", "").ToLowerInvariant()),
      _ when arg.StartsWith("-") => (tpl.dict, arg.Replace("-", "").ToLowerInvariant()),
      _ => (tpl.dict.ApplyPair(tpl.key, arg), "")
    };

  private static IEnumerable<(string, string)> GetPropertyNames<T>() => typeof(T).GetProperties()
    .Select(property => (property.Name, property.Name.ToLowerInvariant()));

  public static string Convert2Json<T>(string[] args) =>
    JSON.SerializeDynamic(MapProperties<T>(GetArgumentNamePairs(args)), new Options(
      serializationNameFormat:
      SerializationNameFormat.CamelCase)
    );
}