[json] add datetime support

pkg/json/CHANGELOG.md

@@ -1,3 +1,7 @@
+# 0.20.3
+
+- Add support for DateTime, serializing it to an ISO-8601 String.
+
 # 0.20.2
 
 - Fix generated code syntax error when defining fields containing the dollar sign `$` by using raw strings.

pkg/json/README.md

@@ -55,6 +55,8 @@ class Manager extends User {
 
 All native JSON types are supported (`int`, `double`, `String`, `bool`, `Null`).
 
+Supports `DateTime`, serializing it to an ISO-8601 String.
+
 The core collection types `List`, `Set`, and `Map` are also supported, if their
 elements are supported types. For elements which require more than just a cast,
 the type must be statically provided through a generic type argument on the

pkg/json/lib/json.dart

@@ -378,6 +378,16 @@ mixin _FromJson on _Shared {
             ' as ',
             type.code,
           ]);
+        case 'DateTime':
+          return RawCode.fromParts([
+            if (nullCheck != null) nullCheck,
+            await builder.resolveIdentifier(_dartCore, 'DateTime'),
+            '.parse(',
+            jsonReference,
+            ' as ',
+            introspectionData.stringCode,
+            ')'
+          ]);
       }
     }
 
@@ -624,6 +634,8 @@ mixin _ToJson on _Shared {
           ]);
         case 'int' || 'double' || 'num' || 'String' || 'bool':
           return valueReference;
+        case 'DateTime':
+          return RawCode.fromParts([valueReference, '.toIso8601String()']);
       }
     }
 

pkg/json/pubspec.yaml

@@ -5,7 +5,7 @@ description: >
   `toJson` encoding method.
 
 repository: https://github.com/dart-lang/sdk/tree/main/pkg/json
-version: 0.20.2
+version: 0.20.3
 environment:
   sdk: ^3.6.0-edge
 dependencies:

pkg/json/test/json_codable_test.dart

@@ -16,6 +16,7 @@ void main() {
         'intField': 10,
         'doubleField': 12.5,
         'numField': 11,
+        'dateTimeField': '2024-11-11T03:42:29.108308',
         'listOfSerializableField': [
           {'x': 1},
         ],
@@ -33,6 +34,7 @@ void main() {
       expect(a.intField, 10);
       expect(a.doubleField, 12.5);
       expect(a.numField, 11);
+      expect(a.dateTimeField, DateTime.parse('2024-11-11T03:42:29.108308'));
       expect(a.listOfSerializableField.single.x, 1);
       expect(a.setOfSerializableField.single.x, 2);
       expect(a.mapOfSerializableField['c']!.x, 3);
@@ -47,6 +49,7 @@ void main() {
         'nullableIntField': 9,
         'nullableDoubleField': 11.5,
         'nullableNumField': 11.1,
+        'nullableDateTimeField': '2024-11-11T03:42:29.108308',
         'nullableListOfSerializableField': [
           {'x': 1},
         ],
@@ -64,6 +67,8 @@ void main() {
       expect(b.nullableIntField, 9);
       expect(b.nullableDoubleField, 11.5);
       expect(b.nullableNumField, 11.1);
+      expect(b.nullableDateTimeField,
+          DateTime.parse('2024-11-11T03:42:29.108308'));
       expect(b.nullableListOfSerializableField!.single.x, 1);
       expect(b.nullableSetOfSerializableField!.single.x, 2);
       expect(b.nullableMapOfSerializableField!['d']!.x, 3);
@@ -78,6 +83,7 @@ void main() {
         'nullableIntField': null,
         'nullableDoubleField': null,
         'nullableNumField': null,
+        'nullableDateTimeField': null,
         'nullableListOfSerializableField': null,
         'nullableSetOfSerializableField': null,
         'nullableMapOfSerializableField': null,
@@ -87,6 +93,7 @@ void main() {
       expect(b.nullableIntField, null);
       expect(b.nullableDoubleField, null);
       expect(b.nullableNumField, null);
+      expect(b.nullableDateTimeField, null);
       expect(b.nullableListOfSerializableField, null);
       expect(b.nullableMapOfSerializableField, null);
       expect(b.nullableSetOfSerializableField, null);
@@ -101,6 +108,7 @@ void main() {
       expect(b.nullableIntField, null);
       expect(b.nullableDoubleField, null);
       expect(b.nullableNumField, null);
+      expect(b.nullableDateTimeField, null);
       expect(b.nullableListOfSerializableField, null);
       expect(b.nullableMapOfSerializableField, null);
       expect(b.nullableSetOfSerializableField, null);
@@ -223,6 +231,8 @@ class A {
 
   final num numField;
 
+  final DateTime dateTimeField;
+
   final List<C> listOfSerializableField;
 
   final Set<C> setOfSerializableField;
@@ -242,6 +252,8 @@ class B {
 
   final num? nullableNumField;
 
+  final DateTime? nullableDateTimeField;
+
   final List<C>? nullableListOfSerializableField;
 
   final Set<C>? nullableSetOfSerializableField;