chore(deps): Target System.Text.Json 10

CHANGELOG.md

@@ -9,9 +9,13 @@ The `Unreleased` section name is replaced by the expected version of next releas
 ## [Unreleased]
 
 ### Added
+
+- `SystemTextJson.Options.CreateWeb`: New method to create web-optimized serializer options based on `JsonSerializerOptions.Web` (STJ 10+) with camelCase naming, case-insensitive deserialization, and number-from-string support [#129](https://github.com/jet/FsCodec/pull/129)
+
 ### Changed
 
 - `SystemTextJson`: Upped minimum `System.Text.Json` version to `10.0.` [#129](https://github.com/jet/FsCodec/pull/129)
+- `SystemTextJson.UnionConverter`: Optimized to use `WriteRawValue` for better performance when writing JSON (STJ 10+) [#129](https://github.com/jet/FsCodec/pull/129)
 
 ### Removed
 ### Fixed

README.md

@@ -122,6 +122,7 @@ The respective concrete Codec packages include relevant `Converter`/`JsonConvert
   - `(autoTypeSafeEnumToJsonString = true)`: triggers usage of `TypeSafeEnumConverter` for any F# Discriminated Unions that only contain nullary cases. See [`AutoUnionTests.fs`](https://github.com/jet/FsCodec/blob/master/tests/FsCodec.SystemTextJson.Tests/AutoUnionTests.fs) for examples  
   - `(autoUnionToJsonObject = true)`: triggers usage of a `UnionConverter` to round-trip F# Discriminated Unions (with at least a single case that has a body) as JSON Object structures. See [`AutoUnionTests.fs`](https://github.com/jet/FsCodec/blob/master/tests/FsCodec.SystemTextJson.Tests/AutoUnionTests.fs) for examples
   - `(rejectNullStrings = true)`: triggers usage of [`RejectNullStringConverter`](https://github.com/jet/FsCodec/blob/master/src/FsCodec.SystemTextJson/RejectNullStringConverter.fs) to reject `null` as a value for strings (`string option` can be used to handle them explicitly).
+- `CreateWeb`: _(System.Text.Json 10+)_ creates web-optimized serializer options based on `JsonSerializerOptions.Web`. Provides camelCase property naming, case-insensitive property matching for deserialization, and allows reading numbers from strings - optimized for typical web API scenarios. Supports the same converter options as `Create` (`autoTypeSafeEnumToJsonString`, `autoUnionToJsonObject`, `rejectNullStrings`).
 - `Default`: Default settings; same as calling `Create()` produces (same intent as [`JsonSerializerOptions.Default`](https://github.com/dotnet/runtime/pull/61434)) 
 
 ## `Serdes`

src/FsCodec.SystemTextJson/Options.fs

@@ -75,3 +75,46 @@ type Options private () =
             ?indent = indent,
             ?camelCase = camelCase,
             unsafeRelaxedJsonEscaping = defaultArg unsafeRelaxedJsonEscaping true)
+
+    /// <summary>Creates web-optimized serializer options based on <c>JsonSerializerOptions.Web</c> from System.Text.Json 10+. <br/>
+    /// Features of <c>JsonSerializerOptions.Web</c>: <br/>
+    /// - camelCase property naming <br/>
+    /// - case-insensitive property matching for deserialization <br/>
+    /// - allows reading numbers from strings <br/>
+    /// - optimized for typical web API scenarios <br/>
+    /// This method allows adding custom converters and overriding specific settings while maintaining the web-optimized base configuration.</summary>
+    static member CreateWeb
+        (   // List of converters to apply. Implicit converters may be prepended and/or be used as a default
+            [<Optional; ParamArray>] converters: JsonConverter[],
+            // Use multi-line, indented formatting when serializing JSON; defaults to false.
+            [<Optional; DefaultParameterValue(null)>] ?indent: bool,
+            // Ignore null values in input data, don't render fields with null values; defaults to `false`.
+            [<Optional; DefaultParameterValue(null)>] ?ignoreNulls: bool,
+            // Apply <c>TypeSafeEnumConverter</c> if possible. Defaults to <c>false</c>.
+            [<Optional; DefaultParameterValue(null)>] ?autoTypeSafeEnumToJsonString: bool,
+            // Apply <c>UnionConverter</c> for all Discriminated Unions, if <c>TypeSafeEnumConverter</c> not possible. Defaults to <c>false</c>.
+            [<Optional; DefaultParameterValue(null)>] ?autoUnionToJsonObject: bool,
+            // Apply <c>RejectNullStringConverter</c> in order to have serialization throw on <c>null</c> strings.
+            // Use <c>string option</c> to represent strings that can potentially be <c>null</c>.
+            [<Optional; DefaultParameterValue(null)>] ?rejectNullStrings: bool) =
+        let autoTypeSafeEnumToJsonString = defaultArg autoTypeSafeEnumToJsonString false
+        let autoUnionToJsonObject = defaultArg autoUnionToJsonObject false
+        let rejectNullStrings = defaultArg rejectNullStrings false
+        let indent = defaultArg indent false
+        let ignoreNulls = defaultArg ignoreNulls false
+
+        // Start with JsonSerializerOptions.Web which provides optimized defaults for web scenarios
+        let options = JsonSerializerOptions(JsonSerializerOptions.Web)
+
+        // Add custom converters
+        [|  if rejectNullStrings then yield (RejectNullStringConverter() :> JsonConverter)
+            if autoTypeSafeEnumToJsonString || autoUnionToJsonObject then
+                yield (UnionOrTypeSafeEnumConverterFactory(typeSafeEnum = autoTypeSafeEnumToJsonString, union = autoUnionToJsonObject) :> JsonConverter)
+            if converters <> null then yield! converters |]
+        |> Array.iter options.Converters.Add
+
+        // Apply overrides
+        if indent then options.WriteIndented <- true
+        if ignoreNulls then options.DefaultIgnoreCondition <- JsonIgnoreCondition.WhenWritingNull
+
+        options

src/FsCodec.SystemTextJson/UnionConverter.fs

@@ -37,14 +37,17 @@ type UnionConverter<'T>() =
         let fieldValues = case.deconstruct value
         for fieldInfo, fieldValue in Seq.zip case.fields fieldValues do
             if fieldValue <> null || options.DefaultIgnoreCondition <> Serialization.JsonIgnoreCondition.Always then
-                let element = JsonSerializer.SerializeToElement(fieldValue, fieldInfo.PropertyType, options)
                 if case.fields.Length = 1 && FSharpType.IsRecord(fieldInfo.PropertyType, true) then
                     // flatten the record properties into the same JSON object as the discriminator
+                    // Use WriteRawValue for better performance (STJ 10+)
+                    let element = JsonSerializer.SerializeToElement(fieldValue, fieldInfo.PropertyType, options)
                     for prop in element.EnumerateObject() do
-                        prop.WriteTo writer
+                        writer.WritePropertyName(prop.Name)
+                        writer.WriteRawValue(prop.Value.GetRawText())
                 else
                     writer.WritePropertyName(fieldInfo.Name)
-                    element.WriteTo writer
+                    let element = JsonSerializer.SerializeToElement(fieldValue, fieldInfo.PropertyType, options)
+                    writer.WriteRawValue(element.GetRawText())
         writer.WriteEndObject()
 
     override _.Read(reader, t: Type, options) =