### Install SystemTextJson.JsonDiffPatch NuGet Packages

Source: https://context7.com/weichch/system-text-json-jsondiffpatch/llms.txt

Install the core diff/patch library and any desired test assertion packages via NuGet.

```shell
dotnet add package SystemTextJson.JsonDiffPatch
```

```shell
dotnet add package SystemTextJson.JsonDiffPatch.Xunit
```

```shell
dotnet add package SystemTextJson.JsonDiffPatch.MSTest
```

```shell
dotnet add package SystemTextJson.JsonDiffPatch.NUnit
```

--------------------------------

### JSON Assertions for Unit Testing in C#

Source: https://github.com/weichch/system-text-json-jsondiffpatch/blob/main/README.md

Demonstrates how to use JsonAssert and assertion extensions for xUnit, MSTest, and NUnit to compare JSON objects. Ensure the correct assertion library is imported for your testing framework.

```csharp
var expected = JsonNode.Parse("{\"foo\":\"bar\"}");
var actual = JsonNode.Parse("{\"baz\":\"qux\", \"foo\":\"bar3\"}");

// xUnit
JsonAssert.Equal(expected, actual);
actual.ShouldEqual(expected);
JsonAssert.NotEqual(expected, actual);
actual.ShouldNotEqual(expected);

// MSTest
JsonAssert.AreEqual(expected, actual);
Assert.That.JsonAreEqual(expected, actual);
JsonAssert.AreNotEqual(expected, actual);
Assert.That.JsonAreNotEqual(expected, actual);

// NUnit
JsonAssert.AreEqual(expected, actual);
Assert.That(actual, JsonIs.EqualTo(expected));
JsonAssert.AreNotEqual(expected, actual);
Assert.That(actual, JsonIs.NotEqualTo(expected));
```

--------------------------------

### Configure Default Diff Options

Source: https://github.com/weichch/system-text-json-jsondiffpatch/blob/main/README.md

Sets the default options for diff operations and the default comparison mode for DeepEquals. This allows for consistent behavior across multiple diff calls.

```csharp
// Default diff options
JsonDiffPatcher.DefaultOptions = () => new JsonDiffOptions
{
    JsonElementComparison = JsonElementComparison.Semantic
};
```

```csharp
// Default comparison mode for DeepEquals
JsonDiffPatcher.DefaultComparison = JsonElementComparison.Semantic;
```

--------------------------------

### xUnit JSON Assertions

Source: https://context7.com/weichch/system-text-json-jsondiffpatch/llms.txt

Provides `JsonAssert.Equal` / `NotEqual` and fluent extension methods `ShouldEqual` / `ShouldNotEqual` for xUnit tests, enabling assertions on JSON data structures.

```APIDOC
## xUnit JSON Assertions — `JsonAssert` (xUnit)

The `SystemTextJson.JsonDiffPatch.Xunit` package provides `JsonAssert.Equal` / `NotEqual` and fluent extension methods `ShouldEqual` / `ShouldNotEqual` for xUnit tests.

### Usage

```csharp
using System.Text.Json.Nodes;
using System.Text.Json.JsonDiffPatch;
using System.Text.Json.JsonDiffPatch.Xunit;
using Xunit;

public class MyApiTests
{
    [Fact]
    public void Response_ShouldMatchExpected()
    {
        var expected = JsonNode.Parse(@"{{\"id\":1,\"name\":\"Alice\"}}");
        var actual   = JsonNode.Parse(@"{{\"id\":1,\"name\":\"Alice\"}}");

        // Basic equality (throws JsonEqualException on failure)
        JsonAssert.Equal(expected, actual);

        // Fluent style
        actual.ShouldEqual(expected);

        // With diff output printed on failure
        JsonAssert.Equal(expected, actual, output: true);

        // With custom diff options (semantic comparison)
        var opts = new JsonDiffOptions { JsonElementComparison = JsonElementComparison.Semantic };
        JsonAssert.Equal(expected, actual, opts);

        // With custom output formatter
        JsonAssert.Equal(expected, actual, delta =>
            $"Mismatch detected!\nDelta:\n{delta.ToJsonString()}");

        // Not-equal assertion
        var other = JsonNode.Parse(@"{{\"id\":2}}");
        JsonAssert.NotEqual(expected, other);
        other.ShouldNotEqual(expected);
    }
}
```
```

--------------------------------

### xUnit JSON Assertions with JsonAssert

Source: https://context7.com/weichch/system-text-json-jsondiffpatch/llms.txt

Utilize JsonAssert.Equal/NotEqual and fluent extension methods for xUnit tests to compare JSON structures. Supports basic equality, semantic comparison, and custom output formatting.

```csharp
using System.Text.Json.Nodes;
using System.Text.Json.JsonDiffPatch;
using System.Text.Json.JsonDiffPatch.Xunit;
using Xunit;

public class MyApiTests
{
    [Fact]
    public void Response_ShouldMatchExpected()
    {
        var expected = JsonNode.Parse("{\"id\":1,\"name\":\"Alice\"}");
        var actual   = JsonNode.Parse("{\"id\":1,\"name\":\"Alice\"}");

        // Basic equality (throws JsonEqualException on failure)
        JsonAssert.Equal(expected, actual);

        // Fluent style
        actual.ShouldEqual(expected);

        // With diff output printed on failure
        JsonAssert.Equal(expected, actual, output: true);

        // With custom diff options (semantic comparison)
        var opts = new JsonDiffOptions { JsonElementComparison = JsonElementComparison.Semantic };
        JsonAssert.Equal(expected, actual, opts);

        // With custom output formatter
        JsonAssert.Equal(expected, actual, delta =>
            $"Mismatch detected!\nDelta:\n{delta.ToJsonString()}");

        // Not-equal assertion
        var other = JsonNode.Parse("{\"id\":2}");
        JsonAssert.NotEqual(expected, other);
        other.ShouldNotEqual(expected);
    }
}

```

--------------------------------

### Set Global Defaults for JsonDiffPatcher

Source: https://context7.com/weichch/system-text-json-jsondiffpatch/llms.txt

Configure process-wide defaults for diff options and comparison modes. This avoids repetitive option passing in individual calls.

```csharp
using System.Text.Json.JsonDiffPatch;

// Apply semantic comparison globally for all Diff calls
JsonDiffPatcher.DefaultOptions = () => new JsonDiffOptions
{
    JsonElementComparison = JsonElementComparison.Semantic,
    TextDiffMinLength = 100,
};

// Apply semantic comparison globally for all DeepEquals calls
JsonDiffPatcher.DefaultComparison = JsonElementComparison.Semantic;

// Now all Diff/DeepEquals calls use Semantic comparison by default
var left  = JsonNode.Parse("{ \"n\":1.0 }");
var right = JsonNode.Parse("{ \"n\":1 }");

JsonNode? delta = left.Diff(right);  // null — semantically equal
bool eq = left.DeepEquals(right);    // true  — semantically equal
```

--------------------------------

### Diff JSON Objects and Files

Source: https://github.com/weichch/system-text-json-jsondiffpatch/blob/main/README.md

Demonstrates various ways to generate a diff between JSON data. Supports JsonNode, files, spans, streams, strings, and readers. Options can be provided for custom comparison or RFC 6902 format.

```csharp
// Diff JsonNode
var node1 = JsonNode.Parse("{\"foo\":\"bar\"}");
var node2 = JsonNode.Parse("{\"baz\":\"qux\", \"foo\":\"bar\"}");
var diff = node1.Diff(node2);
```

```csharp
// Diff with options
var diff = node1.Diff(node2, new JsonDiffOptions
{
    JsonElementComparison = JsonElementComparison.Semantic
});
```

```csharp
// Diff and convert delta into RFC 6902 JSON Patch format
var diff = node1.Diff(node2, new JsonPatchDeltaFormatter());
```

```csharp
// Diff JSON files
var diff = JsonDiffPatcher.DiffFile(file1, file2);
```

```csharp
// Diff Span<byte>
var diff = JsonDiffPatcher.Diff(span1, span2);
```

```csharp
// Diff streams
var diff = JsonDiffPatcher.Diff(stream1, stream2);
```

```csharp
// Diff JSON strings
var diff = JsonDiffPatcher.Diff(json1, json2);
```

```csharp
// Diff JSON readers
var diff = JsonDiffPatcher.Diff(ref reader1, ref reader2);
```

--------------------------------

### Global Defaults for Diff and DeepEquals

Source: https://context7.com/weichch/system-text-json-jsondiffpatch/llms.txt

Configure process-wide defaults for diff options and comparison modes. This allows you to set a default comparison strategy, such as `Semantic`, for all subsequent `Diff` and `DeepEquals` calls without needing to specify options each time.

```APIDOC
## `JsonDiffPatcher.DefaultOptions` / `DefaultComparison` — Global Defaults

Set process-wide defaults for diff options and the `DeepEquals` comparison mode so individual call sites don't need to pass options every time.

```csharp
using System.Text.Json.JsonDiffPatch;

// Apply semantic comparison globally for all Diff calls
JsonDiffPatcher.DefaultOptions = () => new JsonDiffOptions
{
    JsonElementComparison = JsonElementComparison.Semantic,
    TextDiffMinLength = 100,
};

// Apply semantic comparison globally for all DeepEquals calls
JsonDiffPatcher.DefaultComparison = JsonElementComparison.Semantic;

// Now all Diff/DeepEquals calls use Semantic comparison by default
var left  = JsonNode.Parse("""{"n":1.0}""" );
var right = JsonNode.Parse("""{"n":1}""" );

JsonNode? delta = left.Diff(right);  // null — semantically equal
bool eq = left.DeepEquals(right);    // true  — semantically equal
```
```

--------------------------------

### Apply Delta with JsonDiffPatcher.Patch and PatchNew

Source: https://context7.com/weichch/system-text-json-jsondiffpatch/llms.txt

Apply a delta document to a JSON node. `Patch` modifies the node in-place, while `PatchNew` returns a deep clone with the delta applied.

```csharp
using System.Text.Json.Nodes;
using System.Text.Json.JsonDiffPatch;

var left  = JsonNode.Parse("{ \"name\":\"Alice\",\"age\":30 }");
var right = JsonNode.Parse("{ \"name\":\"Alice\",\"age\":31,\"city\":\"London\" }");

JsonNode? delta = left.Diff(right);

// In-place patch (mutates left)
JsonNode? node = JsonNode.Parse("{ \"name\":\"Alice\",\"age\":30 }");
JsonDiffPatcher.Patch(ref node, delta);
Console.WriteLine(node); // {"name":"Alice","age":31,"city":"London"}

// Clone-and-patch (leaves original untouched)
var original = JsonNode.Parse("{ \"name\":\"Alice\",\"age\":30 }");
JsonNode? patched = original.PatchNew(delta);
Console.WriteLine(original); // {"name":"Alice","age":30}   — unchanged
Console.WriteLine(patched);  // {"name":"Alice","age":31,"city":"London"}
```

--------------------------------

### Apply Delta using Patch and PatchNew

Source: https://context7.com/weichch/system-text-json-jsondiffpatch/llms.txt

Apply a generated delta to a JSON node. `Patch` modifies the node in-place, while `PatchNew` applies the patch to a deep clone, leaving the original node unchanged.

```APIDOC
## `JsonDiffPatcher.Patch` / `PatchNew` — Apply a Delta

Apply a delta document produced by `Diff` to a JSON node in-place (`Patch`) or to a deep clone (`PatchNew`).

```csharp
using System.Text.Json.Nodes;
using System.Text.Json.JsonDiffPatch;

var left  = JsonNode.Parse("""{"name":"Alice","age":30}""" );
var right = JsonNode.Parse("""{"name":"Alice","age":31,"city":"London"}""" );

JsonNode? delta = left.Diff(right);

// In-place patch (mutates left)
JsonNode? node = JsonNode.Parse("""{"name":"Alice","age":30}""" );
JsonDiffPatcher.Patch(ref node, delta);
Console.WriteLine(node); // {"name":"Alice","age":31,"city":"London"}

// Clone-and-patch (leaves original untouched)
var original = JsonNode.Parse("""{"name":"Alice","age":30}""" );
JsonNode? patched = original.PatchNew(delta);
Console.WriteLine(original); // {"name":"Alice","age":30}   — unchanged
Console.WriteLine(patched);  // {"name":"Alice","age":31,"city":"London"}
```
```

--------------------------------

### Undo Delta using ReversePatch and ReversePatchNew

Source: https://context7.com/weichch/system-text-json-jsondiffpatch/llms.txt

Reverse a previously applied patch to restore a JSON node to its original state. `ReversePatch` performs the reversal in-place, while `ReversePatchNew` returns a new node with the patch reversed.

```APIDOC
## `JsonDiffPatcher.ReversePatch` / `ReversePatchNew` — Undo a Delta

Reverse a previously applied patch to restore a node to its original state.

```csharp
using System.Text.Json.Nodes;
using System.Text.Json.JsonDiffPatch;

var left  = JsonNode.Parse("""{"name":"Alice","age":30}""" );
var right = JsonNode.Parse("""{"name":"Alice","age":31,"city":"London"}""" );

JsonNode? delta = left.Diff(right);

// Apply patch forward
JsonNode? node = left.PatchNew(delta);
Console.WriteLine(node); // {"name":"Alice","age":31,"city":"London"}

// Reverse the patch (in-place)
JsonDiffPatcher.ReversePatch(ref node, delta);
Console.WriteLine(node); // {"name":"Alice","age":30}

// Clone-and-unpatch
JsonNode? restored = right.ReversePatchNew(delta);
Console.WriteLine(restored); // {"name":"Alice","age":30}
```
```

--------------------------------

### NUnit JSON Assertions

Source: https://context7.com/weichch/system-text-json-jsondiffpatch/llms.txt

Utilize JsonAssert.AreEqual/AreNotEqual and constraint-based Assert.That(actual, JsonIs.EqualTo(expected)) for NUnit. Supports direct assertions, constraint-based assertions, and custom output formatters.

```csharp
using System.Text.Json.Nodes;
using System.Text.Json.JsonDiffPatch;
using System.Text.Json.JsonDiffPatch.Nunit;
using NUnit.Framework;

[TestFixture]
public class MyNunitTests
{
    [Test]
    public void Response_ShouldMatchExpected()
    {
        var expected = JsonNode.Parse(""{"items":[1,2,3]}""");
        var actual   = JsonNode.Parse(""{"items":[1,2,3]}""");

        // Direct assertion
        JsonAssert.AreEqual(expected, actual);

        // Constraint-based (integrates with NUnit's fluent Assert.That)
        Assert.That(actual, JsonIs.EqualTo(expected));

        // With diff options passed through the constraint builder
        var opts = new JsonDiffOptions { JsonElementComparison = JsonElementComparison.Semantic };
        Assert.That(actual, JsonIs.EqualTo(expected).WithDiffOptions(opts));

        // With custom output formatter on failure
        Assert.That(actual, JsonIs.EqualTo(expected)
            .WithOutputFormatter(delta => $"Delta: {delta.ToJsonString()}"));

        // Not-equal constraint
        var other = JsonNode.Parse(""{"items":[4,5]}""");
        JsonAssert.AreNotEqual(expected, other);
        Assert.That(other, JsonIs.NotEqualTo(expected));
    }
}
```

--------------------------------

### JsonDiffPatcher.Diff with JsonDiffOptions - Customized Diffing

Source: https://context7.com/weichch/system-text-json-jsondiffpatch/llms.txt

Allows for customized JSON diffing using JsonDiffOptions to control array move detection, text diffing, element comparison, property filtering, and custom comparers.

```APIDOC
## JsonDiffPatcher.Diff with `JsonDiffOptions`

### Description
`JsonDiffOptions` controls array move detection, long-text diffing, element comparison mode, property filtering, and custom value comparers. Pass an instance as the last argument to any `Diff` overload.

### Method
`JsonNode.Diff(JsonNode? right, JsonDiffOptions options)`

### Parameters
#### Request Body (Implicit via Options)
- **options** (`JsonDiffOptions`) - An object to configure diffing behavior:
  - **JsonElementComparison** (`JsonElementComparison`) - Controls how JSON elements are compared (e.g., `Semantic` for value equivalence).
  - **PropertyFilter** (`Func<string, DiffContext, bool>`) - A predicate to filter properties during diffing.
  - **TextDiffMinLength** (`int`) - Minimum length for text diffing.
  - **SuppressDetectArrayMove** (`bool`) - Whether to suppress array move detection.
  - **ArrayItemMatcher** (`Func<ArrayItemMatchContext, bool>`) - Custom logic for matching array items.

### Request Example
```csharp
using System.Text.Json.Nodes;
using System.Text.Json.JsonDiffPatch;
using System.Text.Json.JsonDiffPatch.Diffs;

var left  = JsonNode.Parse(@"{ \"ts\":\"2024-01-01\", \"value\":1.0, \"secret\":\"hidden\" }");
var right = JsonNode.Parse(@"{ \"ts\":\"2024-01-01T00:00:00\", \"value\":1, \"secret\":\"changed\" }");

var options = new JsonDiffOptions
{
    JsonElementComparison = JsonElementComparison.Semantic,
    PropertyFilter = (propertyName, context) => propertyName != "secret",
    TextDiffMinLength = 50,
    SuppressDetectArrayMove = false,
    ArrayItemMatcher = (ref ArrayItemMatchContext ctx) =>
    {
        if (ctx.Left is JsonObject lo && ctx.Right is JsonObject ro &&
            lo["id"]?.GetValue<int>() == ro["id"]?.GetValue<int>())
        {
            ctx.DeepEqual();
            return true;
        }
        return false;
    },
};

JsonNode? delta = left.Diff(right, options);
Console.WriteLine(delta is null ? "Equal (with options)" : delta.ToJsonString());
```

### Response
#### Success Response (200)
- **delta** (`JsonNode?`) - A `JsonNode` representing the differences based on the provided options, or `null` if no differences are found.

#### Response Example
```json
Equal (with options)
```
```

--------------------------------

### Patch and Unpatch JSON Data

Source: https://github.com/weichch/system-text-json-jsondiffpatch/blob/main/README.md

Shows how to apply a generated diff to modify JSON data (patch) or revert changes (unpatch). Supports in-place modification or creating a new patched object.

```csharp
var node1 = JsonNode.Parse("{\"foo\":\"bar\"}");
var node2 = JsonNode.Parse("{\"baz\":\"qux\", \"foo\":\"bar\"}");
var diff = node1.Diff(node2);
// In-place patch
JsonDiffPatcher.Patch(ref node1, diff);
```

```csharp
// Clone & patch
var patched = node1.PatchNew(diff);
```

```csharp
// In-place unpatch
JsonDiffPatcher.ReversePatch(ref node1, diff);
```

```csharp
// Clone & unpatch
var patched = node1.ReversePatchNew(diff);
```

--------------------------------

### Undo Delta with JsonDiffPatcher.ReversePatch and ReversePatchNew

Source: https://context7.com/weichch/system-text-json-jsondiffpatch/llms.txt

Reverse a previously applied patch to restore a JSON node to its original state. `ReversePatch` modifies in-place, `ReversePatchNew` returns a new restored node.

```csharp
using System.Text.Json.Nodes;
using System.Text.Json.JsonDiffPatch;

var left  = JsonNode.Parse("{ \"name\":\"Alice\",\"age\":30 }");
var right = JsonNode.Parse("{ \"name\":\"Alice\",\"age\":31,\"city\":\"London\" }");

JsonNode? delta = left.Diff(right);

// Apply patch forward
JsonNode? node = left.PatchNew(delta);
Console.WriteLine(node); // {"name":"Alice","age":31,"city":"London"}

// Reverse the patch (in-place)
JsonDiffPatcher.ReversePatch(ref node, delta);
Console.WriteLine(node); // {"name":"Alice","age":30}

// Clone-and-unpatch
JsonNode? restored = right.ReversePatchNew(delta);
Console.WriteLine(restored); // {"name":"Alice","age":30}
```

--------------------------------

### Diff Two JSON Nodes using SystemTextJson.JsonDiffPatch

Source: https://context7.com/weichch/system-text-json-jsondiffpatch/llms.txt

Compares two JsonNode objects and returns a delta document compatible with the jsondiffpatch delta format. Returns null if the nodes are equal. Overloads support various input types including strings, byte spans, streams, and files.

```csharp
using System.Text.Json.Nodes;
using System.Text.Json.JsonDiffPatch;

var left  = JsonNode.Parse诬{"name":"Alice","age":30,"roles":["admin"]}");
var right = JsonNode.Parse诬{"name":"Alice","age":31,"roles":["admin","editor"]}");

// Returns null when equal; returns a delta JsonNode when different
JsonNode? delta = left.Diff(right);

if (delta is null)
{
    Console.WriteLine("No differences found.");
}
else
{
    // Delta format compatible with jsondiffpatch
    Console.WriteLine(delta.ToJsonString(new JsonSerializerOptions { WriteIndented = true }));
    // Output:
    // {
    //   "age": [30, 31],
    //   "roles": {
    //     "_t": "a",
    //     "1": ["editor"]
    //   }
    // }
}

// Diff from JSON strings directly
JsonNode? delta2 = JsonDiffPatcher.Diff(
    "{\"foo\":\"bar\"}",
    "{\"foo\":\"baz\",\"extra\":1}"
);

// Diff from files
JsonNode? fileDelta = JsonDiffPatcher.DiffFile("left.json", "right.json");

// Diff from byte spans (zero-allocation path)
ReadOnlySpan<byte> spanLeft  = "{\"x\":1}"u8;
ReadOnlySpan<byte> spanRight = "{\"x\":2}"u8;
JsonNode? spanDelta = JsonDiffPatcher.Diff(spanLeft, spanRight);
```

```csharp
using System.Text.Json.Nodes;
using System.Text.Json.JsonDiffPatch;
using System.Text.Json.JsonDiffPatch.Diffs;

var left  = JsonNode.Parse诬{"ts":"2024-01-01","value":1.0,"secret":"hidden"}");
var right = JsonNode.Parse诬{"ts":"2024-01-01T00:00:00","value":1,"secret":"changed"}");

var options = new JsonDiffOptions
{
    // Treat "1.0" and "1", or "2024-01-01" and "2024-01-01T00:00:00" as equal
    JsonElementComparison = JsonElementComparison.Semantic,

    // Ignore the "secret" property entirely
    PropertyFilter = (propertyName, context) => propertyName != "secret",

    // Enable long-text diffing for strings >= 50 chars using google-diff-match-patch
    TextDiffMinLength = 50,

    // Suppress array move detection (treat moves as delete+add)
    SuppressDetectArrayMove = false,

    // Custom array item matcher: match objects by their "id" field
    ArrayItemMatcher = (ref ArrayItemMatchContext ctx) =>
    {
        if (ctx.Left is JsonObject lo && ctx.Right is JsonObject ro &&
            lo["id"]?.GetValue<int>() == ro["id"]?.GetValue<int>())
        {
            ctx.DeepEqual(); // mark as deeply equal if all other fields match
            return true;     // these items match
        }
        return false;
    },
};

JsonNode? delta = left.Diff(right, options);
// delta is null because "ts" and "value" are semantically equal,
// and "secret" is filtered out
Console.WriteLine(delta is null ? "Equal (with options)" : delta.ToJsonString());
```

--------------------------------

### MSTest v2 JSON Assertions

Source: https://context7.com/weichch/system-text-json-jsondiffpatch/llms.txt

Use JsonAssert.AreEqual/AreNotEqual and Assert.That.JsonAreEqual for MSTest v2. Supports direct assertions, assertions with output on failure, and assertions with custom diff options.

```csharp
using System.Text.Json.Nodes;
using System.Text.Json.JsonDiffPatch;
using System.Text.Json.JsonDiffPatch.MsTest;
using Microsoft.VisualStudio.TestTools.UnitTesting;

[TestClass]
public class MyMsTests
{
    [TestMethod]
    public void Response_ShouldMatchExpected()
    {
        var expected = JsonNode.Parse(""{"status":"ok","count":3}""");
        var actual   = JsonNode.Parse(""{"status":"ok","count":3}""");

        // Direct assertion
        JsonAssert.AreEqual(expected, actual);

        // With output on failure
        JsonAssert.AreEqual(expected, actual, output: true);

        // Via Assert extension method
        Assert.That.JsonAreEqual(expected, actual);

        // With diff options
        var opts = new JsonDiffOptions { JsonElementComparison = JsonElementComparison.Semantic };
        JsonAssert.AreEqual(expected, actual, opts);

        // Not-equal assertion
        var other = JsonNode.Parse(""{"status":"error"}""");
        JsonAssert.AreNotEqual(expected, other);
        Assert.That.JsonAreNotEqual(expected, other);
    }
}
```

--------------------------------

### Deep Equality Comparison for JSON

Source: https://github.com/weichch/system-text-json-jsondiffpatch/blob/main/README.md

Compares JSON structures for equality using different modes: raw text, semantic, or default. Supports JsonDocument and JsonNode.

```csharp
// JsonDocument
var doc1 = JsonDocument.Parse("{\"foo\":1}");
var doc2 = JsonDocument.Parse("{\"foo\":1.0}");
var equal = doc1.DeepEquals(doc2);
var textEqual = doc1.DeepEquals(doc2, JsonElementComparison.RawText);
var semanticEqual = doc1.DeepEquals(doc2, JsonElementComparison.Semantic);
```

```csharp
// JsonNode
var node1 = JsonNode.Parse("{\"foo\":1}");
var node2 = JsonNode.Parse("{\"foo\":1.0}");
var equal = node1.DeepEquals(node2);
var textEqual = node1.DeepEquals(node2, JsonElementComparison.RawText);
var semanticEqual = node1.DeepEquals(node2, JsonElementComparison.Semantic);
```

--------------------------------

### Generate RFC 6902 JSON Patch with JsonPatchDeltaFormatter

Source: https://context7.com/weichch/system-text-json-jsondiffpatch/llms.txt

Obtain an RFC 6902 JSON Patch array instead of the default jsondiffpatch delta format. Supports custom options.

```csharp
using System.Text.Json.Nodes;
using System.Text.Json.JsonDiffPatch;
using System.Text.Json.JsonDiffPatch.Diffs.Formatters;

var left  = JsonNode.Parse("{ \"name\":\"Alice\",\"age\":30 }");
var right = JsonNode.Parse("{ \"name\":\"Alice\",\"age\":31,\"city\":\"London\" }");

// Returns JsonNode representing a RFC 6902 patch array
JsonNode? patch = left.Diff(right, new JsonPatchDeltaFormatter());

Console.WriteLine(patch?.ToJsonString(new JsonSerializerOptions { WriteIndented = true }));
// Output:
// [
//   { "op": "replace", "path": "/age",  "value": 31 },
//   { "op": "add",     "path": "/city", "value": "London" }
// ]

// Overload with options
var options = new JsonDiffOptions { JsonElementComparison = JsonElementComparison.Semantic };
JsonNode? patch2 = left.Diff(right, new JsonPatchDeltaFormatter(), options);
```

--------------------------------

### Semantic Value Comparison

Source: https://github.com/weichch/system-text-json-jsondiffpatch/blob/main/README.md

Compares JSON values semantically, treating numbers with different decimal representations as equal and dates in string format as equal. Useful for ignoring minor formatting differences.

```csharp
var node1 = JsonNode.Parse("\"2019-11-27\"");
var node2 = JsonNode.Parse("\"2019-11-27T00:00:00.000\"");
// dateCompare is 0
var dateCompare = JsonValueComparer.Compare(node1, node2);
```

```csharp
var node3 = JsonNode.Parse("1");
var node4 = JsonNode.Parse("1.00");
// numCompare is 0
var numCompare = JsonValueComparer.Compare(node3, node4);
```

--------------------------------

### RFC 6902 JSON Patch Output using JsonPatchDeltaFormatter

Source: https://context7.com/weichch/system-text-json-jsondiffpatch/llms.txt

Generate diffs in the standard RFC 6902 JSON Patch format instead of the default jsondiffpatch format. This is useful when interoperating with systems that expect RFC 6902 compliant patches.

```APIDOC
## `JsonDiffPatcher.Diff` with `JsonPatchDeltaFormatter` — RFC 6902 JSON Patch Output

Use `JsonPatchDeltaFormatter` to obtain a standard RFC 6902 JSON Patch array instead of the jsondiffpatch delta format.

```csharp
using System.Text.Json.Nodes;
using System.Text.Json.JsonDiffPatch;
using System.Text.Json.JsonDiffPatch.Diffs.Formatters;

var left  = JsonNode.Parse("""{"name":"Alice","age":30}""" );
var right = JsonNode.Parse("""{"name":"Alice","age":31,"city":"London"}""" );

// Returns JsonNode representing a RFC 6902 patch array
JsonNode? patch = left.Diff(right, new JsonPatchDeltaFormatter());

Console.WriteLine(patch?.ToJsonString(new JsonSerializerOptions { WriteIndented = true }));
// Output:
// [
//   { "op": "replace", "path": "/age",  "value": 31 },
//   { "op": "add",     "path": "/city", "value": "London" }
// ]

// Overload with options
var options = new JsonDiffOptions { JsonElementComparison = JsonElementComparison.Semantic };
JsonNode? patch2 = left.Diff(right, new JsonPatchDeltaFormatter(), options);
```
```

--------------------------------

### JsonDiffPatcher.Diff - Diff Two JSON Nodes

Source: https://context7.com/weichch/system-text-json-jsondiffpatch/llms.txt

Compares two JsonNode objects and returns a delta document. It handles various input types including strings, byte spans, streams, and JsonNodes. Returns null if the nodes are identical.

```APIDOC
## JsonDiffPatcher.Diff

### Description
Compares two `JsonNode?` objects and returns a delta document (`JsonNode?`). Returns `null` if the two nodes are equal. Overloads accept `string`, `ReadOnlySpan<byte>`, `Stream`, `Utf8JsonReader`, or `JsonNode` inputs.

### Method
`JsonNode.Diff(JsonNode? right)`
`JsonDiffPatcher.Diff(string leftJson, string rightJson)`
`JsonDiffPatcher.DiffFile(string leftFilePath, string rightFilePath)`
`JsonDiffPatcher.Diff(ReadOnlySpan<byte> left, ReadOnlySpan<byte> right)`

### Request Example
```csharp
using System.Text.Json.Nodes;
using System.Text.Json.JsonDiffPatch;

var left  = JsonNode.Parse(@"{ \"name\":\"Alice\", \"age\":30, \"roles\":[\"admin\"] }");
var right = JsonNode.Parse(@"{ \"name\":\"Alice\", \"age\":31, \"roles\":[\"admin\",\"editor\"] }");

JsonNode? delta = left.Diff(right);

if (delta is null)
{
    Console.WriteLine("No differences found.");
}
else
{
    Console.WriteLine(delta.ToJsonString(new JsonSerializerOptions { WriteIndented = true }));
}

// Diff from JSON strings directly
JsonNode? delta2 = JsonDiffPatcher.Diff(
    @"{ \"foo\":\"bar\" }",
    @"{ \"foo\":\"baz\", \"extra\":1 }"
);

// Diff from files
JsonNode? fileDelta = JsonDiffPatcher.DiffFile("left.json", "right.json");

// Diff from byte spans (zero-allocation path)
ReadOnlySpan<byte> spanLeft  = @"{ \"x\":1 }"u8;
ReadOnlySpan<byte> spanRight = @"{ \"x\":2 }"u8;
JsonNode? spanDelta = JsonDiffPatcher.Diff(spanLeft, spanRight);
```

### Response
#### Success Response (200)
- **delta** (`JsonNode?`) - A `JsonNode` representing the differences, or `null` if no differences are found.

#### Response Example
```json
{
  "age": [30, 31],
  "roles": {
    "_t": "a",
    "1": ["editor"]
  }
}
```
```

--------------------------------

### JsonValueComparer.Compare

Source: https://context7.com/weichch/system-text-json-jsondiffpatch/llms.txt

Compares two `JsonValue` instances semantically, treating numerically or temporally equivalent values as equal. Returns negative, zero, or positive like standard `IComparer<T>`.

```APIDOC
## `JsonValueComparer.Compare` — Semantic Comparison of JsonValue

Compares two `JsonValue` instances semantically, treating numerically or temporally equivalent values as equal. Returns negative, zero, or positive like standard `IComparer<T>`.

### Usage

```csharp
using System.Text.Json.Nodes;
using System.Text.Json.JsonDiffPatch;

// Date string comparison
var date1 = JsonNode.Parse("\"2019-11-27\")")!.AsValue();
var date2 = JsonNode.Parse("\"2019-11-27T00:00:00.000\")")!.AsValue();
int dateCmp = JsonValueComparer.Compare(date1, date2);
Console.WriteLine(dateCmp); // 0 — semantically equal dates

// Numeric comparison
var num1 = JsonNode.Parse("1")!.AsValue();
var num2 = JsonNode.Parse("1.00")!.AsValue();
int numCmp = JsonValueComparer.Compare(num1, num2);
Console.WriteLine(numCmp);  // 0 — semantically equal numbers

// Integer ordering
var a = JsonNode.Parse("5")!.AsValue();
var b = JsonNode.Parse("10")!.AsValue();
Console.WriteLine(JsonValueComparer.Compare(a, b)); // negative (5 < 10)
Console.WriteLine(JsonValueComparer.Compare(b, a)); // positive (10 > 5)

// Use as a custom IEqualityComparer<JsonValue> inside JsonDiffOptions
var options = new JsonDiffOptions
{
    ValueComparer = EqualityComparer<JsonValue>.Create(
        (x, y) => JsonValueComparer.Compare(x, y) == 0,
        x => x.GetHashCode()
    )
};
```
```

--------------------------------

### DeepEquals for JsonNode, JsonDocument, JsonElement

Source: https://context7.com/weichch/system-text-json-jsondiffpatch/llms.txt

Use DeepEquals to determine structural equality of JSON values. Supports RawText or Semantic comparison modes. Property order does not affect equality for JsonNode.

```csharp
using System.Text.Json;
using System.Text.Json.Nodes;
using System.Text.Json.JsonDiffPatch;

// --- JsonNode ---
var n1 = JsonNode.Parse("{\"a\":1,\"b\":[1,2]}");
var n2 = JsonNode.Parse("{\"b\":[1,2],\"a\":1}");  // property order differs

bool eq1 = n1.DeepEquals(n2);  // true — order-insensitive
bool eq2 = n1.DeepEquals(n2, JsonElementComparison.Semantic); // true

// Numeric semantic equality: 1 == 1.00
var x = JsonNode.Parse("1");
var y = JsonNode.Parse("1.00");
Console.WriteLine(x.DeepEquals(y));                                  // false (RawText)
Console.WriteLine(x.DeepEquals(y, JsonElementComparison.Semantic));  // true

// --- JsonDocument ---
using var doc1 = JsonDocument.Parse("{\"foo\":1}");
using var doc2 = JsonDocument.Parse("{\"foo\":1.0}");
Console.WriteLine(doc1.DeepEquals(doc2));                                         // false (RawText)
Console.WriteLine(doc1.DeepEquals(doc2, JsonElementComparison.Semantic));         // true

// --- JsonElement ---
JsonElement elem1 = JsonDocument.Parse("{\"k\":\"2024-01-01\"}").RootElement;
JsonElement elem2 = JsonDocument.Parse("{\"k\":\"2024-01-01\"}").RootElement;
Console.WriteLine(elem1.DeepEquals(elem2));                                       // true
```

--------------------------------

### JsonDiffPatcher.DeepEquals

Source: https://context7.com/weichch/system-text-json-jsondiffpatch/llms.txt

Determines structural equality of two JSON values (`JsonNode`, `JsonDocument`, `JsonElement`). Supports optional `RawText` (default) or `Semantic` comparison modes.

```APIDOC
## `JsonDiffPatcher.DeepEquals` — Deep Equality for JsonNode, JsonDocument, JsonElement

Determines structural equality of two JSON values. Supports `JsonNode`, `JsonDocument`, and `JsonElement`, with optional `RawText` (default) or `Semantic` comparison modes.

### Usage

```csharp
using System.Text.Json;
using System.Text.Json.Nodes;
using System.Text.Json.JsonDiffPatch;

// --- JsonNode ---
var n1 = JsonNode.Parse(@"{{\"a\":1,\"b\":[1,2]}}");
var n2 = JsonNode.Parse(@"{{\"b\":[1,2],\"a\":1}}");  // property order differs

bool eq1 = n1.DeepEquals(n2);  // true — order-insensitive
bool eq2 = n1.DeepEquals(n2, JsonElementComparison.Semantic); // true

// Numeric semantic equality: 1 == 1.00
var x = JsonNode.Parse("1");
var y = JsonNode.Parse("1.00");
Console.WriteLine(x.DeepEquals(y));                                  // false (RawText)
Console.WriteLine(x.DeepEquals(y, JsonElementComparison.Semantic));  // true

// --- JsonDocument ---
using var doc1 = JsonDocument.Parse(@"{{\"foo\":1}}");
using var doc2 = JsonDocument.Parse(@"{{\"foo\":1.0}}");
Console.WriteLine(doc1.DeepEquals(doc2));                                         // false (RawText)
Console.WriteLine(doc1.DeepEquals(doc2, JsonElementComparison.Semantic));         // true

// --- JsonElement ---
JsonElement elem1 = JsonDocument.Parse(@"{{\"k\":\"2024-01-01\"}}").RootElement;
JsonElement elem2 = JsonDocument.Parse(@"{{\"k\":\"2024-01-01\"}}").RootElement;
Console.WriteLine(elem1.DeepEquals(elem2));                                       // true
```
```

--------------------------------

### JsonValueComparer for Semantic Comparison

Source: https://context7.com/weichch/system-text-json-jsondiffpatch/llms.txt

Use JsonValueComparer.Compare to semantically compare JsonValue instances, treating numerically or temporally equivalent values as equal. This can be used to create custom IEqualityComparer<JsonValue> for JsonDiffOptions.

```csharp
using System.Text.Json.Nodes;
using System.Text.Json.JsonDiffPatch;

// Date string comparison
var date1 = JsonNode.Parse("  \"2019-11-27\"            ")!.AsValue();
var date2 = JsonNode.Parse("  \"2019-11-27T00:00:00.000\" ")!.AsValue();
int dateCmp = JsonValueComparer.Compare(date1, date2);
Console.WriteLine(dateCmp); // 0 — semantically equal dates

// Numeric comparison
var num1 = JsonNode.Parse("1")!.AsValue();
var num2 = JsonNode.Parse("1.00")!.AsValue();
int numCmp = JsonValueComparer.Compare(num1, num2);
Console.WriteLine(numCmp);  // 0 — semantically equal numbers

// Integer ordering
var a = JsonNode.Parse("5")!.AsValue();
var b = JsonNode.Parse("10")!.AsValue();
Console.WriteLine(JsonValueComparer.Compare(a, b)); // negative (5 < 10)
Console.WriteLine(JsonValueComparer.Compare(b, a)); // positive (10 > 5)

// Use as a custom IEqualityComparer<JsonValue> inside JsonDiffOptions
var options = new JsonDiffOptions
{
    ValueComparer = EqualityComparer<JsonValue>.Create(
        (x, y) => JsonValueComparer.Compare(x, y) == 0,
        x => x.GetHashCode()
    )
};

```

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