Added createJsonKeys

json_annotation/lib/src/json_serializable.dart

@@ -87,6 +87,21 @@ class JsonSerializable {
   /// such as [fieldRename].
   final bool? createFieldMap;
 
+  /// If `true` (defaults to false), a private class `_$ExampleJsonKeys`
+  /// constant is created in the generated part file.
+  ///
+  /// This class will contain every property, with the json key as value,
+  /// exposing a secured way to access the json key from the property.
+  ///
+  /// ```dart
+  /// @JsonSerializable(createJsonKeys: true)
+  /// class Example {
+  ///   // ...
+  ///   static const jsonKeys = _$PublicationImplJsonKeys();
+  /// }
+  /// ```
+  final bool? createJsonKeys;
+
   /// If `true` (defaults to false), a private, static `_$ExamplePerFieldToJson`
   /// abstract class will be generated in the part file.
   ///
@@ -247,6 +262,7 @@ class JsonSerializable {
     this.checked,
     this.constructor,
     this.createFieldMap,
+    this.createJsonKeys,
     this.createFactory,
     this.createToJson,
     this.disallowUnrecognizedKeys,

json_serializable/README.md

@@ -1,24 +1,23 @@
 <!-- This content is generated. See tool/readme/readme_template.md -->
 [![Pub Package](https://img.shields.io/pub/v/json_serializable.svg)](https://pub.dev/packages/json_serializable)
 
-Provides [Dart Build System] builders for handling JSON.
+Provides [Dart Build System][Dart Build System] builders for handling JSON.
 
 The builders generate code when they find members annotated with classes defined
-in [package:json_annotation].
+in [package:json_annotation][package:json_annotation].
 
 - To generate to/from JSON code for a class, annotate it with
   [`JsonSerializable`]. You can provide arguments to [`JsonSerializable`] to
   configure the generated code. You can also customize individual fields by
   annotating them with [`JsonKey`] and providing custom arguments. See the
   table below for details on the [annotation values](#annotation-values).
-
 - To generate a Dart field with the contents of a file containing JSON, use the
   [`JsonLiteral`] annotation.
 
 ## Setup
 
 To configure your project for the latest released version of
-`json_serializable`, see the [example].
+`json_serializable`, see the [example][example].
 
 ## Example
 
@@ -85,8 +84,8 @@ code will be generated when you build. There are three ways to control how code
 is generated:
 
 1. Setting properties on [`JsonKey`] annotating the target field.
-1. Set properties on [`JsonSerializable`] annotating the target type.
-1. Add configuration to `build.yaml` – [see below](#build-configuration).
+2. Set properties on [`JsonSerializable`] annotating the target type.
+3. Add configuration to `build.yaml` – [see below](#build-configuration).
 
 Every [`JsonSerializable`] field is configurable via `build.yaml`. If you find
 you want all or most of your classes with the same configuration, it may be
@@ -106,7 +105,7 @@ Annotate `enum` types with [`JsonEnum`] (new in `json_annotation` 4.2.0) to:
 1. Specify the default rename logic for each enum value using `fieldRename`. For
    instance, use `fieldRename: FieldRename.kebab` to encode `enum` value
    `noGood` as `"no-good"`.
-1. Force the generation of the `enum` helpers, even if the `enum` is not
+2. Force the generation of the `enum` helpers, even if the `enum` is not
    referenced in code. This is an edge scenario, but useful for some.
 
 Annotate `enum` values with [`JsonValue`] to specify the encoded value to map
@@ -147,16 +146,20 @@ enum StatusCodeEnhanced {
 
 Out of the box, `json_serializable` supports many common types in the
 [dart:core](https://api.dart.dev/stable/dart-core/dart-core-library.html)
-library: 
+library:
+
 [`BigInt`], [`bool`], [`DateTime`], [`double`], [`Duration`], [`Enum`], [`int`],
 [`Iterable`], [`List`], [`Map`], [`num`], [`Object`], [`Record`], [`Set`],
 [`String`], [`Uri`]
 
 The collection types –
+
 [`Iterable`], [`List`], [`Map`], [`Record`], [`Set`]
+
 – can contain values of all the above types.
 
 For [`Map`], the key value must be one of
+
 [`BigInt`], [`DateTime`], [`Enum`], [`int`], [`Object`], [`String`], [`Uri`]
 
 # Custom types and custom encoding
@@ -169,92 +172,90 @@ customize the encoding/decoding of any type, you have a few options.
    for these types, you don't have to! The generator code only looks for these
    methods. It doesn't care how they were created.
 
-    ```dart
-    @JsonSerializable()
-    class Sample1 {
-      Sample1(this.value);
-
-      factory Sample1.fromJson(Map<String, dynamic> json) =>
-          _$Sample1FromJson(json);
+   ```dart
+   @JsonSerializable()
+   class Sample1 {
+     Sample1(this.value);
 
-      // Sample2 is NOT annotated with @JsonSerializable(), but that's okay
-      // The class has a `fromJson` constructor and a `toJson` method, which is
-      // all that is required.
-      final Sample2 value;
+     factory Sample1.fromJson(Map<String, dynamic> json) =>
+         _$Sample1FromJson(json);
 
-      Map<String, dynamic> toJson() => _$Sample1ToJson(this);
-    }
+     // Sample2 is NOT annotated with @JsonSerializable(), but that's okay
+     // The class has a `fromJson` constructor and a `toJson` method, which is
+     // all that is required.
+     final Sample2 value;
 
-    class Sample2 {
-      Sample2(this.value);
+     Map<String, dynamic> toJson() => _$Sample1ToJson(this);
+   }
 
-      // The convention is for `fromJson` to take a single parameter of type
-      // `Map<String, dynamic>` but any JSON-compatible type is allowed.
-      factory Sample2.fromJson(int value) => Sample2(value);
-      final int value;
+   class Sample2 {
+     Sample2(this.value);
 
-      // The convention is for `toJson` to take return a type of
-      // `Map<String, dynamic>` but any JSON-compatible type is allowed.
-      int toJson() => value;
-    }
-    ```
+     // The convention is for `fromJson` to take a single parameter of type
+     // `Map<String, dynamic>` but any JSON-compatible type is allowed.
+     factory Sample2.fromJson(int value) => Sample2(value);
+     final int value;
 
-1. Use the [`JsonKey.toJson`] and [`JsonKey.fromJson`] properties to specify
+     // The convention is for `toJson` to take return a type of
+     // `Map<String, dynamic>` but any JSON-compatible type is allowed.
+     int toJson() => value;
+   }
+   ```
+2. Use the [`JsonKey.toJson`] and [`JsonKey.fromJson`] properties to specify
    custom conversions on the annotated field. The functions specified must be
    top-level or static. See the documentation of these properties for details.
 
-    ```dart
-    @JsonSerializable()
-    class Sample3 {
-      Sample3(this.value);
-
-      factory Sample3.fromJson(Map<String, dynamic> json) =>
-          _$Sample3FromJson(json);
+   ```dart
+   @JsonSerializable()
+   class Sample3 {
+     Sample3(this.value);
 
-      @JsonKey(
-        toJson: _toJson,
-        fromJson: _fromJson,
-      )
-      final DateTime value;
+     factory Sample3.fromJson(Map<String, dynamic> json) =>
+         _$Sample3FromJson(json);
 
-      Map<String, dynamic> toJson() => _$Sample3ToJson(this);
+     @JsonKey(
+       toJson: _toJson,
+       fromJson: _fromJson,
+     )
+     final DateTime value;
 
-      static int _toJson(DateTime value) => value.millisecondsSinceEpoch;
-      static DateTime _fromJson(int value) =>
-          DateTime.fromMillisecondsSinceEpoch(value);
-    }
-    ```
+     Map<String, dynamic> toJson() => _$Sample3ToJson(this);
 
-1. Create an implementation of [`JsonConverter`] and annotate either the
+     static int _toJson(DateTime value) => value.millisecondsSinceEpoch;
+     static DateTime _fromJson(int value) =>
+         DateTime.fromMillisecondsSinceEpoch(value);
+   }
+   ```
+3. Create an implementation of [`JsonConverter`] and annotate either the
    corresponding field or the containing class. [`JsonConverter`] is convenient
    if you want to use the same conversion logic on many fields. It also allows
    you to support a type within collections. Check out
    [these examples](https://github.com/google/json_serializable.dart/blob/master/example/lib/json_converter_example.dart).
 
-    ```dart
-    @JsonSerializable()
-    class Sample4 {
-      Sample4(this.value);
+   ```dart
+   @JsonSerializable()
+   class Sample4 {
+     Sample4(this.value);
 
-      factory Sample4.fromJson(Map<String, dynamic> json) =>
-          _$Sample4FromJson(json);
+     factory Sample4.fromJson(Map<String, dynamic> json) =>
+         _$Sample4FromJson(json);
 
-      @EpochDateTimeConverter()
-      final DateTime value;
+     @EpochDateTimeConverter()
+     final DateTime value;
 
-      Map<String, dynamic> toJson() => _$Sample4ToJson(this);
-    }
+     Map<String, dynamic> toJson() => _$Sample4ToJson(this);
+   }
 
-    class EpochDateTimeConverter implements JsonConverter<DateTime, int> {
-      const EpochDateTimeConverter();
+   class EpochDateTimeConverter implements JsonConverter<DateTime, int> {
+     const EpochDateTimeConverter();
 
-      @override
-      DateTime fromJson(int json) => DateTime.fromMillisecondsSinceEpoch(json);
+     @override
+     DateTime fromJson(int json) => DateTime.fromMillisecondsSinceEpoch(json);
 
-      @override
-      int toJson(DateTime object) => object.millisecondsSinceEpoch;
-    }
-    ```
+     @override
+     int toJson(DateTime object) => object.millisecondsSinceEpoch;
+   }
+   ```
 
 # Build configuration
 
@@ -276,6 +277,7 @@ targets:
           constructor: ""
           create_factory: true
           create_field_map: false
+          create_json_keys: false
           create_per_field_to_json: false
           create_to_json: true
           disallow_unrecognized_keys: false
@@ -297,15 +299,15 @@ targets:
 [`Enum`]: https://api.dart.dev/stable/dart-core/Enum-class.html
 [`int`]: https://api.dart.dev/stable/dart-core/int-class.html
 [`Iterable`]: https://api.dart.dev/stable/dart-core/Iterable-class.html
-[`JsonConverter`]: https://pub.dev/documentation/json_annotation/4.8.1/json_annotation/JsonConverter-class.html
-[`JsonEnum.valueField`]: https://pub.dev/documentation/json_annotation/4.8.1/json_annotation/JsonEnum/valueField.html
-[`JsonEnum`]: https://pub.dev/documentation/json_annotation/4.8.1/json_annotation/JsonEnum-class.html
-[`JsonKey.fromJson`]: https://pub.dev/documentation/json_annotation/4.8.1/json_annotation/JsonKey/fromJson.html
-[`JsonKey.toJson`]: https://pub.dev/documentation/json_annotation/4.8.1/json_annotation/JsonKey/toJson.html
-[`JsonKey`]: https://pub.dev/documentation/json_annotation/4.8.1/json_annotation/JsonKey-class.html
-[`JsonLiteral`]: https://pub.dev/documentation/json_annotation/4.8.1/json_annotation/JsonLiteral-class.html
-[`JsonSerializable`]: https://pub.dev/documentation/json_annotation/4.8.1/json_annotation/JsonSerializable-class.html
-[`JsonValue`]: https://pub.dev/documentation/json_annotation/4.8.1/json_annotation/JsonValue-class.html
+[`JsonConverter`]: https://pub.dev/documentation/json_annotation/latest/json_annotation/JsonConverter-class.html
+[`JsonEnum.valueField`]: https://pub.dev/documentation/json_annotation/latest/json_annotation/JsonEnum/valueField.html
+[`JsonEnum`]: https://pub.dev/documentation/json_annotation/latest/json_annotation/JsonEnum-class.html
+[`JsonKey.fromJson`]: https://pub.dev/documentation/json_annotation/latest/json_annotation/JsonKey/fromJson.html
+[`JsonKey.toJson`]: https://pub.dev/documentation/json_annotation/latest/json_annotation/JsonKey/toJson.html
+[`JsonKey`]: https://pub.dev/documentation/json_annotation/latest/json_annotation/JsonKey-class.html
+[`JsonLiteral`]: https://pub.dev/documentation/json_annotation/latest/json_annotation/JsonLiteral-class.html
+[`JsonSerializable`]: https://pub.dev/documentation/json_annotation/latest/json_annotation/JsonSerializable-class.html
+[`JsonValue`]: https://pub.dev/documentation/json_annotation/latest/json_annotation/JsonValue-class.html
 [`List`]: https://api.dart.dev/stable/dart-core/List-class.html
 [`Map`]: https://api.dart.dev/stable/dart-core/Map-class.html
 [`num`]: https://api.dart.dev/stable/dart-core/num-class.html

json_serializable/lib/src/encoder_helper.dart

@@ -63,6 +63,26 @@ mixin EncodeHelper implements HelperCore {
     return buffer.toString();
   }
 
+  /// Generates an object containing metadatas related to the encoding,
+  /// destined to be used by other code-generators.
+  String createJsonKeys(Set<FieldElement> accessibleFieldSet) {
+    assert(config.createJsonKeys);
+
+    final buffer = StringBuffer(
+      'class _\$${element.name.nonPrivate}JsonKeys {',
+    )..write('const _\$${element.name.nonPrivate}JsonKeys();');
+
+    for (final field in accessibleFieldSet) {
+      buffer.writeln(
+        'final String ${field.name} = ${escapeDartString(nameAccess(field))};',
+      );
+    }
+
+    buffer.write('}');
+
+    return buffer.toString();
+  }
+
   Iterable<String> createToJson(Set<FieldElement> accessibleFields) sync* {
     assert(config.createToJson);
 

json_serializable/lib/src/generator_helper.dart

@@ -132,6 +132,10 @@ class GeneratorHelper extends HelperCore with EncodeHelper, DecodeHelper {
       yield createFieldMap(accessibleFieldSet);
     }
 
+    if (config.createJsonKeys) {
+      yield createJsonKeys(accessibleFieldSet);
+    }
+
     if (config.createPerFieldToJson) {
       yield createPerFieldToJson(accessibleFieldSet);
     }

json_serializable/lib/src/type_helpers/config_types.dart

@@ -49,6 +49,7 @@ class ClassConfig {
   final bool createFactory;
   final bool createToJson;
   final bool createFieldMap;
+  final bool createJsonKeys;
   final bool createPerFieldToJson;
   final bool disallowUnrecognizedKeys;
   final bool explicitToJson;
@@ -66,6 +67,7 @@ class ClassConfig {
     required this.createFactory,
     required this.createToJson,
     required this.createFieldMap,
+    required this.createJsonKeys,
     required this.createPerFieldToJson,
     required this.disallowUnrecognizedKeys,
     required this.explicitToJson,
@@ -85,6 +87,8 @@ class ClassConfig {
         constructor: config.constructor ?? ClassConfig.defaults.constructor,
         createFieldMap:
             config.createFieldMap ?? ClassConfig.defaults.createFieldMap,
+        createJsonKeys:
+            config.createJsonKeys ?? ClassConfig.defaults.createJsonKeys,
         createPerFieldToJson: config.createPerFieldToJson ??
             ClassConfig.defaults.createPerFieldToJson,
         createFactory:
@@ -113,6 +117,7 @@ class ClassConfig {
     createFactory: true,
     createToJson: true,
     createFieldMap: false,
+    createJsonKeys: false,
     createPerFieldToJson: false,
     disallowUnrecognizedKeys: false,
     explicitToJson: false,
@@ -129,6 +134,7 @@ class ClassConfig {
         createFactory: createFactory,
         createToJson: createToJson,
         createFieldMap: createFieldMap,
+        createJsonKeys: createJsonKeys,
         createPerFieldToJson: createPerFieldToJson,
         ignoreUnannotated: ignoreUnannotated,
         explicitToJson: explicitToJson,