Add GroupBy method for Z.DynamicLinq.SystemTextJson and Z.DynamicLinq.NewtonsoftJson (#929)

StefH · web-flow · commit 3208964fa494 · 2025-06-06T20:41:20.000+02:00
* Add GroupBy method for Z.DynamicLinq.SystemTextJson and Z.DynamicLinq.NewtonsoftJson

* .
diff --git a/src/System.Linq.Dynamic.Core.NewtonsoftJson/NewtonsoftJsonExtensions.cs b/src/System.Linq.Dynamic.Core.NewtonsoftJson/NewtonsoftJsonExtensions.cs
@@ -2,6 +2,7 @@
 using System.Linq.Dynamic.Core.NewtonsoftJson.Config;
 using System.Linq.Dynamic.Core.NewtonsoftJson.Extensions;
 using System.Linq.Dynamic.Core.Validation;
+using JetBrains.Annotations;
 using Newtonsoft.Json.Linq;
 
 namespace System.Linq.Dynamic.Core.NewtonsoftJson;
@@ -303,6 +304,42 @@ public static JToken First(this JArray source, string predicate, params object?[
     }
     #endregion FirstOrDefault
 
+    #region GroupBy
+    /// <summary>
+    /// Groups the elements of a sequence according to a specified key string function 
+    /// and creates a result value from each group and its key.
+    /// </summary>
+    /// <param name="source">A <see cref="JArray"/> whose elements to group.</param>
+    /// <param name="keySelector">A string expression to specify the key for each element.</param>
+    /// <param name="args">An object array that contains zero or more objects to insert into the predicate as parameters. Similar to the way String.Format formats strings.</param>
+    /// <returns>A <see cref="JArray"/> where each element represents a projection over a group and its key.</returns>
+    [PublicAPI]
+    public static JArray GroupBy(this JArray source, string keySelector, params object[]? args)
+    {
+        return GroupBy(source, NewtonsoftJsonParsingConfig.Default, keySelector, args);
+    }
+
+    /// <summary>
+    /// Groups the elements of a sequence according to a specified key string function 
+    /// and creates a result value from each group and its key.
+    /// </summary>
+    /// <param name="source">A <see cref="JArray"/> whose elements to group.</param>
+    /// <param name="config">The <see cref="NewtonsoftJsonParsingConfig"/>.</param>
+    /// <param name="keySelector">A string expression to specify the key for each element.</param>
+    /// <param name="args">An object array that contains zero or more objects to insert into the predicate as parameters. Similar to the way String.Format formats strings.</param>
+    /// <returns>A <see cref="JArray"/> where each element represents a projection over a group and its key.</returns>
+    [PublicAPI]
+    public static JArray GroupBy(this JArray source, NewtonsoftJsonParsingConfig config, string keySelector, params object[]? args)
+    {
+        Check.NotNull(source);
+        Check.NotNull(config);
+        Check.NotNullOrEmpty(keySelector);
+
+        var queryable = ToQueryable(source, config);
+        return ToJArray(() => queryable.GroupBy(config, keySelector, args));
+    }
+    #endregion
+
     #region Last
     /// <summary>
     /// Returns the last element of a sequence that satisfies a specified condition.
@@ -813,7 +850,17 @@ private static JArray ToJArray(Func<IQueryable> func)
         var array = new JArray();
         foreach (var dynamicElement in func())
         {
-            var element = dynamicElement is DynamicClass dynamicClass ? JObject.FromObject(dynamicClass) : dynamicElement;
+            var element = dynamicElement switch
+            {
+                IGrouping<object, object> grouping => new JObject
+                {
+                    [nameof(grouping.Key)] = JToken.FromObject(grouping.Key),
+                    ["Values"] = ToJArray(grouping.AsQueryable)
+                },
+                DynamicClass dynamicClass => JObject.FromObject(dynamicClass),
+                _ => dynamicElement
+            };
+
             array.Add(element);
         }
 
diff --git a/src/System.Linq.Dynamic.Core.SystemTextJson/SystemTextJsonExtensions.cs b/src/System.Linq.Dynamic.Core.SystemTextJson/SystemTextJsonExtensions.cs
@@ -5,6 +5,7 @@
 using System.Linq.Dynamic.Core.SystemTextJson.Utils;
 using System.Linq.Dynamic.Core.Validation;
 using System.Text.Json;
+using JetBrains.Annotations;
 
 namespace System.Linq.Dynamic.Core.SystemTextJson;
 
@@ -371,6 +372,42 @@ public static JsonElement First(this JsonDocument source, string predicate, para
     }
     #endregion FirstOrDefault
 
+    #region GroupBy
+    /// <summary>
+    /// Groups the elements of a sequence according to a specified key string function 
+    /// and creates a result value from each group and its key.
+    /// </summary>
+    /// <param name="source">A <see cref="JsonDocument"/> whose elements to group.</param>
+    /// <param name="keySelector">A string expression to specify the key for each element.</param>
+    /// <param name="args">An object array that contains zero or more objects to insert into the predicate as parameters. Similar to the way String.Format formats strings.</param>
+    /// <returns>A <see cref="JsonDocument"/> where each element represents a projection over a group and its key.</returns>
+    [PublicAPI]
+    public static JsonDocument GroupBy(this JsonDocument source, string keySelector, params object[]? args)
+    {
+        return GroupBy(source, SystemTextJsonParsingConfig.Default, keySelector, args);
+    }
+
+    /// <summary>
+    /// Groups the elements of a sequence according to a specified key string function 
+    /// and creates a result value from each group and its key.
+    /// </summary>
+    /// <param name="source">A <see cref="JsonDocument"/> whose elements to group.</param>
+    /// <param name="config">The <see cref="SystemTextJsonParsingConfig"/>.</param>
+    /// <param name="keySelector">A string expression to specify the key for each element.</param>
+    /// <param name="args">An object array that contains zero or more objects to insert into the predicate as parameters. Similar to the way String.Format formats strings.</param>
+    /// <returns>A <see cref="JsonDocument"/> where each element represents a projection over a group and its key.</returns>
+    [PublicAPI]
+    public static JsonDocument GroupBy(this JsonDocument source, SystemTextJsonParsingConfig config, string keySelector, params object[]? args)
+    {
+        Check.NotNull(source);
+        Check.NotNull(config);
+        Check.NotNullOrEmpty(keySelector);
+
+        var queryable = ToQueryable(source, config);
+        return ToJsonDocumentArray(() => queryable.GroupBy(config, keySelector, args));
+    }
+    #endregion
+
     #region Last
     /// <summary>
     /// Returns the last element of a sequence.
@@ -1037,7 +1074,17 @@ private static JsonDocument ToJsonDocumentArray(Func<IQueryable> func)
         var array = new List<object?>();
         foreach (var dynamicElement in func())
         {
-            array.Add(ToJsonElement(dynamicElement));
+            var element = dynamicElement switch
+            {
+                IGrouping<object, object> grouping => ToJsonElement(new
+                {
+                    Key = ToJsonElement(grouping.Key),
+                    Values = ToJsonDocumentArray(grouping.AsQueryable).RootElement
+                }),
+                _ => ToJsonElement(dynamicElement)
+            };
+
+            array.Add(element);
         }
 
         return JsonDocumentUtils.FromObject(array);
diff --git a/test/System.Linq.Dynamic.Core.NewtonsoftJson.Tests/NewtonsoftJsonTests.cs b/test/System.Linq.Dynamic.Core.NewtonsoftJson.Tests/NewtonsoftJsonTests.cs
@@ -168,6 +168,88 @@ public void FirstOrDefault()
         _source.FirstOrDefault("Age > 999").Should().BeNull();
     }
 
+    [Fact]
+    public void GroupBySimpleKeySelector()
+    {
+        // Arrange
+        var json =
+            """
+            [
+              {
+                "Name": "Mr. Test Smith",
+                "Type": "PAY",
+                "Something": {
+                  "Field1": "Test1",
+                  "Field2": "Test2"
+                }
+              },
+              {
+                "Name": "Mr. Test Smith",
+                "Type": "DISPATCH",
+                "Something": {
+                  "Field1": "Test1",
+                  "Field2": "Test2"
+                }
+              },
+              {
+                "Name": "Different Name",
+                "Type": "PAY",
+                "Something": {
+                  "Field1": "Test3",
+                  "Field2": "Test4"
+                }
+              }
+            ]
+            """;
+        var source = JArray.Parse(json);
+
+        // Act
+        var resultAsJson = source.GroupBy("Type").ToString();
+
+        // Assert
+        var expected =
+            """
+            [
+              {
+                "Key": "PAY",
+                "Values": [
+                  {
+                    "Name": "Mr. Test Smith",
+                    "Type": "PAY",
+                    "Something": {
+                      "Field1": "Test1",
+                      "Field2": "Test2"
+                    }
+                  },
+                  {
+                    "Name": "Different Name",
+                    "Type": "PAY",
+                    "Something": {
+                      "Field1": "Test3",
+                      "Field2": "Test4"
+                    }
+                  }
+                ]
+              },
+              {
+                "Key": "DISPATCH",
+                "Values": [
+                  {
+                    "Name": "Mr. Test Smith",
+                    "Type": "DISPATCH",
+                    "Something": {
+                      "Field1": "Test1",
+                      "Field2": "Test2"
+                    }
+                  }
+                ]
+              }
+            ]
+            """;
+
+        resultAsJson.Should().Be(expected);
+    }
+
     [Fact]
     public void Last()
     {
diff --git a/test/System.Linq.Dynamic.Core.SystemTextJson.Tests/SystemTextJsonTests.cs b/test/System.Linq.Dynamic.Core.SystemTextJson.Tests/SystemTextJsonTests.cs
@@ -6,6 +6,11 @@ namespace System.Linq.Dynamic.Core.SystemTextJson.Tests;
 
 public class SystemTextJsonTests
 {
+    private static readonly JsonSerializerOptions _options = new()
+    {
+        WriteIndented = true
+    };
+
     private const string ExampleJsonObjectArray =
         """
         [
@@ -142,7 +147,7 @@ public void Distinct()
                 }
             ]
             """;
-        var source = JsonDocument.Parse(json);
+        using var source = JsonDocument.Parse(json);
 
         // Act
         var result = source.Select("Name").Distinct();
@@ -174,6 +179,89 @@ public void FirstOrDefault()
         _source.FirstOrDefault("Age > 999").Should().BeNull();
     }
 
+    [Fact]
+    public void GroupBySimpleKeySelector()
+    {
+        // Arrange
+        var json =
+            """
+            [
+              {
+                "Name": "Mr. Test Smith",
+                "Type": "PAY",
+                "Something": {
+                  "Field1": "Test1",
+                  "Field2": "Test2"
+                }
+              },
+              {
+                "Name": "Mr. Test Smith",
+                "Type": "DISPATCH",
+                "Something": {
+                  "Field1": "Test1",
+                  "Field2": "Test2"
+                }
+              },
+              {
+                "Name": "Different Name",
+                "Type": "PAY",
+                "Something": {
+                  "Field1": "Test3",
+                  "Field2": "Test4"
+                }
+              }
+            ]
+            """;
+        using var source = JsonDocument.Parse(json);
+
+        // Act
+        var result = source.GroupBy("Type");
+        var resultAsJson = JsonSerializer.Serialize(result, _options);
+
+        // Assert
+        var expected =
+            """
+            [
+              {
+                "Key": "PAY",
+                "Values": [
+                  {
+                    "Name": "Mr. Test Smith",
+                    "Type": "PAY",
+                    "Something": {
+                      "Field1": "Test1",
+                      "Field2": "Test2"
+                    }
+                  },
+                  {
+                    "Name": "Different Name",
+                    "Type": "PAY",
+                    "Something": {
+                      "Field1": "Test3",
+                      "Field2": "Test4"
+                    }
+                  }
+                ]
+              },
+              {
+                "Key": "DISPATCH",
+                "Values": [
+                  {
+                    "Name": "Mr. Test Smith",
+                    "Type": "DISPATCH",
+                    "Something": {
+                      "Field1": "Test1",
+                      "Field2": "Test2"
+                    }
+                  }
+                ]
+              }
+            ]
+            """;
+
+        resultAsJson.Should().Be(expected);
+    }
+
     [Fact]
     public void Last()
     {
@@ -265,7 +353,7 @@ public void OrderBy_Multiple()
                }
             ]
             """;
-        var source = JsonDocument.Parse(json);
+        using var source = JsonDocument.Parse(json);
 
         // Act
         var result = source.OrderBy("Age, Name").Select("Name");
@@ -279,7 +367,7 @@ public void OrderBy_Multiple()
     public void Page()
     {
         var json = "[1, 2, 3, 4, 5, 6, 7, 8, 9, 0]";
-        var source = JsonDocument.Parse(json);
+        using var source = JsonDocument.Parse(json);
 
         // Act
         var result = source.Page(2, 3);
@@ -293,7 +381,7 @@ public void Page()
     public void PageResult()
     {
         var json = "[1, 2, 3, 4, 5, 6, 7, 8, 9, 0]";
-        var source = JsonDocument.Parse(json);
+        using var source = JsonDocument.Parse(json);
 
         // Act
         var pagedResult = source.PageResult(2, 3);
@@ -339,7 +427,7 @@ public void SelectMany()
                    ]
                }]
             """;
-        var source = JsonDocument.Parse(json);
+        using var source = JsonDocument.Parse(json);
 
         // Act
         var result = source
