Fix Json when property value is null

src/System.Linq.Dynamic.Core.NewtonsoftJson/Config/NewtonsoftJsonParsingConfig.cs

@@ -10,7 +10,10 @@ public class NewtonsoftJsonParsingConfig : ParsingConfig
     /// <summary>
     /// The default ParsingConfig for <see cref="NewtonsoftJsonParsingConfig"/>.
     /// </summary>
-    public new static NewtonsoftJsonParsingConfig Default { get; } = new();
+    public new static NewtonsoftJsonParsingConfig Default { get; } = new NewtonsoftJsonParsingConfig
+    {
+        ConvertObjectToSupportComparison = true
+    };
 
     /// <summary>
     /// The default <see cref="DynamicJsonClassOptions"/> to use.
@@ -28,7 +31,7 @@ public class NewtonsoftJsonParsingConfig : ParsingConfig
     /// <remarks>
     /// Use this property to control how the normalization process handles properties that are missing or undefined.
     /// The selected behavior may affect the output or error handling of normalization operations.
-    /// The default value is <see cref="NormalizationNonExistingPropertyBehavior.UseDefaultValue"/>.
+    /// The default value is <see cref="NormalizationNonExistingPropertyBehavior.UseNull"/>.
     /// </remarks>
     public NormalizationNonExistingPropertyBehavior NormalizationNonExistingPropertyValueBehavior { get; set; }
 }

src/System.Linq.Dynamic.Core.NewtonsoftJson/Config/NormalizationNonExistingPropertyBehavior.cs

@@ -6,12 +6,12 @@
 public enum NormalizationNonExistingPropertyBehavior
 {
     /// <summary>
-    /// Specifies that the default value should be used.
+    /// Specifies that a null value should be used.
     /// </summary>
-    UseDefaultValue = 0,
+    UseNull = 0,
 
     /// <summary>
-    /// Specifies that null values should be used.
+    /// Specifies that the default value should be used.
     /// </summary>
-    UseNull = 1
+    UseDefaultValue = 1    
 }

src/System.Linq.Dynamic.Core.NewtonsoftJson/Extensions/JObjectExtensions.cs

@@ -44,10 +44,7 @@ private class JTokenResolvers : Dictionary<JTokenType, Func<JToken, DynamicJsonC
         foreach (var prop in src.Properties())
         {
             var value = Resolvers[prop.Type](prop.Value, options);
-            if (value != null)
-            {
-                dynamicPropertiesWithValue.Add(new DynamicPropertyWithValue(prop.Name, value));
-            }
+            dynamicPropertiesWithValue.Add(new DynamicPropertyWithValue(prop.Name, value));
         }
 
         return DynamicClassFactory.CreateInstance(dynamicPropertiesWithValue);

src/System.Linq.Dynamic.Core.NewtonsoftJson/NewtonsoftJsonExtensions.cs

@@ -871,8 +871,11 @@ private static JArray ToJArray(Func<IQueryable> func)
 
     private static IQueryable ToQueryable(JArray source, NewtonsoftJsonParsingConfig? config = null)
     {
-        var normalized = config?.Normalize == true ?
-            NormalizeUtils.NormalizeArray(source, config.NormalizationNonExistingPropertyValueBehavior):
+        config = config ?? NewtonsoftJsonParsingConfig.Default;
+        config.ConvertObjectToSupportComparison = true;
+
+        var normalized = config.Normalize == true ?
+            NormalizeUtils.NormalizeArray(source, config.NormalizationNonExistingPropertyValueBehavior) :
             source;
 
         return normalized

src/System.Linq.Dynamic.Core.NewtonsoftJson/Utils/NormalizeUtils.cs

@@ -86,7 +86,7 @@ private static JObject NormalizeObject(JObject source, Dictionary<string, JsonVa
                 }
                 else
                 {
-                    result[key] = normalizationBehavior == NormalizationNonExistingPropertyBehavior.UseDefaultValue ? GetDefaultValue(schema[key]) : JValue.CreateNull();
+                    result[key] = GetDefaultOrNullValue(normalizationBehavior, schema[key]);
                 }
             }
         }
@@ -105,7 +105,7 @@ private static JObject CreateEmptyObject(Dictionary<string, JsonValueInfo> schem
             }
             else
             {
-                obj[key] = normalizationBehavior == NormalizationNonExistingPropertyBehavior.UseDefaultValue ? GetDefaultValue(schema[key]) : JValue.CreateNull();
+                obj[key] = GetDefaultOrNullValue(normalizationBehavior, schema[key]);
             }
         }
 
@@ -125,7 +125,28 @@ private static JToken GetDefaultValue(JsonValueInfo jType)
             JTokenType.Integer => default(int),
             JTokenType.String => string.Empty,
             JTokenType.TimeSpan => TimeSpan.MinValue,
+            _ => GetNullValue(jType),
+        };
+    }
+
+    private static JValue GetNullValue(JsonValueInfo jType)
+    {
+        return jType.Type switch
+        {
+            JTokenType.Boolean => new JValue((bool?)null),
+            JTokenType.Bytes => new JValue((byte[]?)null),
+            JTokenType.Date => new JValue((DateTime?)null),
+            JTokenType.Float => new JValue((float?)null),
+            JTokenType.Guid => new JValue((Guid?)null),
+            JTokenType.Integer => new JValue((int?)null),
+            JTokenType.String => new JValue((string?)null),
+            JTokenType.TimeSpan => new JValue((TimeSpan?)null),
             _ => JValue.CreateNull(),
         };
     }
+
+    private static JToken GetDefaultOrNullValue(NormalizationNonExistingPropertyBehavior behavior, JsonValueInfo jType)
+    {
+        return behavior == NormalizationNonExistingPropertyBehavior.UseDefaultValue ? GetDefaultValue(jType) : GetNullValue(jType);
+    }
 }

src/System.Linq.Dynamic.Core.SystemTextJson/Config/NormalizationNonExistingPropertyBehavior.cs

@@ -1,17 +1,17 @@
 namespace System.Linq.Dynamic.Core.SystemTextJson.Config;
 
 /// <summary>
-/// Specifies the behavior to use when setting a property vlue that does not exist or is missing during normalization.
+/// Specifies the behavior to use when setting a property value that does not exist or is missing during normalization.
 /// </summary>
 public enum NormalizationNonExistingPropertyBehavior
 {
     /// <summary>
-    /// Specifies that the default value should be used.
+    /// Specifies that a null value should be used.
     /// </summary>
-    UseDefaultValue = 0,
+    UseNull = 0,
 
     /// <summary>
-    /// Specifies that null values should be used.
+    /// Specifies that the default value should be used.
     /// </summary>
-    UseNull = 1
+    UseDefaultValue = 1    
 }

src/System.Linq.Dynamic.Core.SystemTextJson/Config/SystemTextJsonParsingConfig.cs

@@ -24,7 +24,7 @@ public class SystemTextJsonParsingConfig : ParsingConfig
     /// <remarks>
     /// Use this property to control how the normalization process handles properties that are missing or undefined.
     /// The selected behavior may affect the output or error handling of normalization operations.
-    /// The default value is <see cref="NormalizationNonExistingPropertyBehavior.UseDefaultValue"/>.
+    /// The default value is <see cref="NormalizationNonExistingPropertyBehavior.UseNull"/>.
     /// </remarks>
     public NormalizationNonExistingPropertyBehavior NormalizationNonExistingPropertyValueBehavior { get; set; }
 }

src/System.Linq.Dynamic.Core.SystemTextJson/Extensions/JsonDocumentExtensions.cs

@@ -34,10 +34,7 @@ private class JTokenResolvers : Dictionary<JsonValueKind, Func<JsonElement, Dyna
         foreach (var prop in src.Value.EnumerateObject())
         {
             var value = Resolvers[prop.Value.ValueKind](prop.Value, options);
-            if (value != null)
-            {
-                dynamicPropertiesWithValue.Add(new DynamicPropertyWithValue(prop.Name, value));
-            }
+            dynamicPropertiesWithValue.Add(new DynamicPropertyWithValue(prop.Name, value));
         }
 
         return DynamicClassFactory.CreateInstance(dynamicPropertiesWithValue);
@@ -129,7 +126,7 @@ private static IEnumerable ConvertJsonElementToEnumerable(JsonElement arg, Dynam
     private static IEnumerable ConvertToTypedArray(IEnumerable<object?> src, Type newType)
     {
         var method = ConvertToTypedArrayGenericMethod.MakeGenericMethod(newType);
-        return (IEnumerable)method.Invoke(null, new object[] { src })!;
+        return (IEnumerable)method.Invoke(null, [src])!;
     }
 
     private static readonly MethodInfo ConvertToTypedArrayGenericMethod = typeof(JsonDocumentExtensions).GetMethod(nameof(ConvertToTypedArrayGeneric), BindingFlags.NonPublic | BindingFlags.Static)!;

src/System.Linq.Dynamic.Core.SystemTextJson/Utils/NormalizeUtils.cs

@@ -104,15 +104,16 @@ private static JsonObject NormalizeObject(JsonObject source, Dictionary<string,
             {
                 if (source.ContainsKey(key))
                 {
+                    var value = source[key];
 #if NET8_0_OR_GREATER
-                    result[key] = source[key]!.DeepClone();
+                    result[key] = value?.DeepClone();
 #else
-                    result[key] = JsonNode.Parse(source[key]!.ToJsonString());
+                    result[key] = value != null ? JsonNode.Parse(value.ToJsonString()) : null;
 #endif
                 }
                 else
                 {
-                    result[key] = normalizationBehavior == NormalizationNonExistingPropertyBehavior.UseDefaultValue ? GetDefaultValue(jType) : null;
+                    result[key] = GetDefaultOrNullValue(normalizationBehavior, jType);
                 }
             }
         }
@@ -134,7 +135,7 @@ private static JsonObject CreateEmptyObject(Dictionary<string, JsonValueInfo> sc
             }
             else
             {
-                obj[key] = normalizationBehavior == NormalizationNonExistingPropertyBehavior.UseDefaultValue ? GetDefaultValue(jType) : null;
+                obj[key] = GetDefaultOrNullValue(normalizationBehavior, jType);
             }
         }
 
@@ -150,7 +151,25 @@ private static JsonObject CreateEmptyObject(Dictionary<string, JsonValueInfo> sc
             JsonValueKind.Number => default(int),
             JsonValueKind.String => string.Empty,
             JsonValueKind.True => false,
+            _ => GetNullValue(jType),
+        };
+    }
+
+    private static JsonNode? GetNullValue(JsonValueInfo jType)
+    {
+        return jType.Type switch
+        {
+            JsonValueKind.Array => null,
+            JsonValueKind.False => JsonValue.Create<bool?>(false),
+            JsonValueKind.Number => JsonValue.Create<int?>(null),
+            JsonValueKind.String => JsonValue.Create<string?>(null),
+            JsonValueKind.True => JsonValue.Create<bool?>(true),
             _ => null,
         };
     }
+
+    private static JsonNode? GetDefaultOrNullValue(NormalizationNonExistingPropertyBehavior behavior, JsonValueInfo jType)
+    {
+        return behavior == NormalizationNonExistingPropertyBehavior.UseDefaultValue ? GetDefaultValue(jType) : GetNullValue(jType);
+    }
 }

test/System.Linq.Dynamic.Core.NewtonsoftJson.Tests/NewtonsoftJsonTests.cs

@@ -1,5 +1,4 @@
-using System.Linq.Dynamic.Core.Exceptions;
-using System.Linq.Dynamic.Core.NewtonsoftJson.Config;
+using System.Linq.Dynamic.Core.NewtonsoftJson.Config;
 using FluentAssertions;
 using Newtonsoft.Json.Linq;
 using Xunit;
@@ -13,11 +12,13 @@ public class NewtonsoftJsonTests
         [
             {
                 "Name": "John",
-                "Age": 30
+                "Age": 30,
+                "IsNull": null
             },
             {
                 "Name": "Doe",
-                "Age": 40
+                "Age": 40,
+                "AlsoNull": null
             }
         ]
         """;
@@ -567,6 +568,6 @@ public void NormalizeArray_When_NormalizeIsFalse_ShouldThrow()
         Action act = () => JArray.Parse(array).Where(config, "Age >= 30");
 
         // Assert
-        act.Should().Throw<InvalidOperationException>().WithMessage("The binary operator GreaterThanOrEqual is not defined for the types 'System.Object' and 'System.Int32'.");
+        act.Should().Throw<InvalidOperationException>().WithMessage("Unable to find property 'Age' on type '<>*");
     }
 }

test/System.Linq.Dynamic.Core.SystemTextJson.Tests/SystemTextJsonTests.cs

@@ -17,11 +17,13 @@ public class SystemTextJsonTests
         [
             {
                 "Name": "John",
-                "Age": 30
+                "Age": 30,
+                "IsNull": null
             },
             {
                 "Name": "Doe",
-                "Age": 40
+                "Age": 40,
+                "AlsoNull": null
             }
         ]
         """;
@@ -161,20 +163,20 @@ public void Distinct()
     public void First()
     {
         // Act + Assert 1
-        _source.First().GetRawText().Should().BeEquivalentTo(JsonDocument.Parse(@"{""Name"":""John"",""Age"":30}").RootElement.GetRawText());
+        _source.First().GetRawText().Should().BeEquivalentTo(JsonDocument.Parse(@"{""Name"":""John"",""Age"":30,""IsNull"":null,""AlsoNull"":null}").RootElement.GetRawText());
 
         // Act + Assert 2
-        _source.First("Age > 30").GetRawText().Should().BeEquivalentTo(JsonDocument.Parse(@"{""Name"":""Doe"",""Age"":40}").RootElement.GetRawText());
+        _source.First("Age > 30").GetRawText().Should().BeEquivalentTo(JsonDocument.Parse(@"{""Name"":""Doe"",""Age"":40,""IsNull"":null,""AlsoNull"":null}").RootElement.GetRawText());
     }
 
     [Fact]
     public void FirstOrDefault()
     {
         // Act + Assert 1
-        _source.FirstOrDefault()!.Value.GetRawText().Should().BeEquivalentTo(JsonDocument.Parse(@"{""Name"":""John"",""Age"":30}").RootElement.GetRawText());
+        _source.FirstOrDefault()!.Value.GetRawText().Should().BeEquivalentTo(JsonDocument.Parse(@"{""Name"":""John"",""Age"":30,""IsNull"":null,""AlsoNull"":null}").RootElement.GetRawText());
 
         // Act + Assert 2
-        _source.FirstOrDefault("Age > 30")!.Value.GetRawText().Should().BeEquivalentTo(JsonDocument.Parse(@"{""Name"":""Doe"",""Age"":40}").RootElement.GetRawText());
+        _source.FirstOrDefault("Age > 30")!.Value.GetRawText().Should().BeEquivalentTo(JsonDocument.Parse(@"{""Name"":""Doe"",""Age"":40,""IsNull"":null,""AlsoNull"":null}").RootElement.GetRawText());
 
         // Act + Assert 3
         _source.FirstOrDefault("Age > 999").Should().BeNull();
@@ -267,20 +269,20 @@ public void GroupBySimpleKeySelector()
     public void Last()
     {
         // Act + Assert 1
-        _source.Last().GetRawText().Should().BeEquivalentTo(JsonDocument.Parse(@"{""Name"":""Doe"",""Age"":40}").RootElement.GetRawText());
+        _source.Last().GetRawText().Should().BeEquivalentTo(JsonDocument.Parse(@"{""Name"":""Doe"",""Age"":40,""IsNull"":null,""AlsoNull"":null}").RootElement.GetRawText());
 
         // Act + Assert 2
-        _source.Last("Age > 0").GetRawText().Should().BeEquivalentTo(JsonDocument.Parse(@"{""Name"":""Doe"",""Age"":40}").RootElement.GetRawText());
+        _source.Last("Age > 0").GetRawText().Should().BeEquivalentTo(JsonDocument.Parse(@"{""Name"":""Doe"",""Age"":40,""IsNull"":null,""AlsoNull"":null}").RootElement.GetRawText());
     }
 
     [Fact]
     public void LastOrDefault()
     {
         // Act + Assert 1
-        _source.LastOrDefault()!.Value.GetRawText().Should().BeEquivalentTo(JsonDocument.Parse(@"{""Name"":""Doe"",""Age"":40}").RootElement.GetRawText());
+        _source.LastOrDefault()!.Value.GetRawText().Should().BeEquivalentTo(JsonDocument.Parse(@"{""Name"":""Doe"",""Age"":40,""IsNull"":null,""AlsoNull"":null}").RootElement.GetRawText());
 
         // Act + Assert 2
-        _source.LastOrDefault("Age > 0")!.Value.GetRawText().Should().BeEquivalentTo(JsonDocument.Parse(@"{""Name"":""Doe"",""Age"":40}").RootElement.GetRawText());
+        _source.LastOrDefault("Age > 0")!.Value.GetRawText().Should().BeEquivalentTo(JsonDocument.Parse(@"{""Name"":""Doe"",""Age"":40,""IsNull"":null,""AlsoNull"":null}").RootElement.GetRawText());
 
         // Act + Assert 3
         _source.LastOrDefault("Age > 999").Should().BeNull();
@@ -444,7 +446,7 @@ public void SelectMany()
     public void Single()
     {
         // Act + Assert
-        _source.Single("Age > 30").GetRawText().Should().BeEquivalentTo(JsonDocument.Parse(@"{""Name"":""Doe"",""Age"":40}").RootElement.GetRawText());
+        _source.Single("Age > 30").GetRawText().Should().BeEquivalentTo(JsonDocument.Parse(@"{""Name"":""Doe"",""Age"":40,""IsNull"":null,""AlsoNull"":null}").RootElement.GetRawText());
     }
 
     [Fact]