Json.Net JsonConverter for Unity3D types

UnityTypeSupport.cs

using System;
using System.Collections.Generic;
using Newtonsoft.Json;
using Newtonsoft.Json.Converters;
using Newtonsoft.Json.Linq;
using UnityEngine;

internal static class UnityTypeSupport
{
    
#if UNITY_EDITOR
    [UnityEditor.InitializeOnLoadMethod]
#else
    [RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.AfterAssembliesLoaded)]
#endif
    private static void Init()
    {
        JsonConvert.DefaultSettings += GetJsonSerializerSettings;
    }

    private static JsonSerializerSettings GetJsonSerializerSettings()
    {
        var settings = new JsonSerializerSettings();
        settings.Converters.Add(new UnityTypeConverter());
        settings.Converters.Add(new ScriptableObjectCreator());
        return settings;
    }

    private class UnityTypeConverter : JsonConverter
    {
        private static readonly HashSet<Type> UnityEngineTypes;
        
        static UnityTypeConverter()
        {
            UnityEngineTypes = new HashSet<Type>(typeof(UnityEngine.Object).Assembly.GetTypes());
        }
        
        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            writer.WriteRawValue(JsonUtility.ToJson(value));
        }

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            if (typeof(ScriptableObject).IsAssignableFrom(objectType))
            {
                JsonUtility.FromJsonOverwrite(JObject.Load(reader).ToString(), existingValue);
                return existingValue;
            }
            
            return JsonUtility.FromJson(JObject.Load(reader).ToString(), objectType);
        }

        public override bool CanConvert(Type objectType)
        {
            return IsUnityEngineType(objectType);
        }

        private static bool IsUnityEngineType(Type objectType)
        {
            return UnityEngineTypes.Contains(objectType);
        }
    }
    
    private class ScriptableObjectCreator : CustomCreationConverter<ScriptableObject>
    {
        public override ScriptableObject Create(Type objectType)
        {
            return ScriptableObject.CreateInstance(objectType);
        }
    }
}