using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Data;

​

using System.Text.Json;

using System.Text.Json.Serialization;

using System.Text.Json.Serialization.Metadata;

using System.Text.Json.Nodes;

​

using NUnit.Framework; // Throws NUnit.Framework.AssertionException

​

//https://stackoverflow.com/questions/79135596/jsonpath-net-use-query-to-flatten-data-structure

​

using Json.Path;

​

#nullable enable

​

    class TestClass

    {

        public static void Test()

        {

            TestTextValue();

            TestNumValue();

        }

​

        public static void TestTextValue()

        {

            string jsonText = GetJson();

            var rootJsonNode = JsonNode.Parse(jsonText);

            var path = JsonPath.Parse("$..textValue");

            var results = path.Evaluate(rootJsonNode);                        

            var newArray = JsonSerializer.SerializeToNode(results.Matches.Select(m => m.Value))!.AsArray();

            Console.WriteLine(JsonSerializer.Serialize(newArray));

            var expectedJson = 

                """

                [

                  "a1",

                  "b1",

                  "b2"

                ]

                """;

            Assert.That(JsonNode.DeepEquals(newArray, JsonNode.Parse(expectedJson)));

        }   

​

        public static void TestNumValue()

        {

            var root = JsonNode.Parse(GetJson());

            var path = JsonPath.Parse("$..numValue");

            var results = path.Evaluate(root);                        

            var newArray = JsonSerializer.SerializeToNode(results.Matches.Select(m => m.Value))!.AsArray();

            Console.WriteLine(JsonSerializer.Serialize(newArray));

            var expectedJson = 

                """

                [

                  1,

                  1,

                  2             

                ]

                """;

            Assert.That(JsonNode.DeepEquals(newArray, JsonNode.Parse(expectedJson)));

        }   

        static string GetJson() =>

            """

            {

              "ObjA" : {

                "textValue" : "a1",

                "numValue" : 1

              },

              "ObjB" : {

                "objArray": [

                  {

                    "textValue": "b1",

                    "numValue" : 1

                  },

                  {

                    "textValue": "b2",

                    "numValue" : 2

                  }

                ]

              }

            }           

            """;

    }

​

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Environment version: {0} ({1}), {2}", System.Runtime.InteropServices.RuntimeInformation.FrameworkDescription , Environment.Version, Environment.OSVersion);

            Console.WriteLine("System.Text.Json version: " + typeof(JsonSerializer).Assembly.FullName);

            Console.WriteLine("JsonPath.Net version: " + typeof(Json.Path.JsonPath).Assembly.FullName);

            Console.WriteLine();

​

            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

                Console.WriteLine("Failed with unhandled exception: ");

                Console.WriteLine(ex);

                throw;

            }

        }

    }

​