Add support RealmValue.fromJson

CHANGELOG.md

@@ -1,19 +1,5 @@
 ## vNext (TBD)
 
-### Enhancements
-* None
-
-### Fixed
-* None
-
-### Compatibility
-* Realm Studio: 13.0.0 or later.
-
-### Internal
-* Using Core x.y.z.
-
-## 2.0.0-beta.1 (2024-03-18)
-
 ### Breaking Changes
 * `RealmValue.type` is now an enum of type `RealmValueType` rather than `Type`. If you need the runtime type of the value wrapped in `RealmValue`, use `RealmValue.value.runtimeType`. (Issue [#1505](https://github.com/realm/realm-dart/issues/1505))
 * Renamed `RealmValue.uint8List` constructor to `RealmValue.binary`. (PR [#1469](https://github.com/realm/realm-dart/pull/1469))

packages/realm_common/lib/src/realm_types.dart

@@ -1,6 +1,7 @@
 // Copyright 2021 MongoDB, Inc.
 // SPDX-License-Identifier: Apache-2.0
 
+import 'dart:convert';
 import 'dart:math';
 import 'dart:typed_data';
 import 'package:objectid/objectid.dart';
@@ -268,6 +269,14 @@ class RealmValue {
     };
   }
 
+  /// Constructs a RealmValue from a valid json string. The json object must contain only
+  /// values that are supported by [RealmValue].
+  ///
+  /// Throws [FormatException] if the [json] argument is not valid json.
+  factory RealmValue.fromJson(String json) {
+    return RealmValue.from(jsonDecode(json));
+  }
+
   @override
   operator ==(Object? other) {
     // We always return false when comparing two RealmValue collections.

packages/realm_dart/test/realm_value_test.dart

@@ -1203,4 +1203,101 @@ void main() {
       expect(noMatchesQuery, isEmpty);
     });
   });
+
+  group('RealmValue.fromJson', () {
+    test('Throws with invalid json', () {
+      final json = '{ "This is": invalid }';
+
+      expect(() => RealmValue.fromJson(json), throwsA(isA<FormatException>()));
+    });
+
+    test('Constructs objects', () {
+      final json = '{ "1.1": { "2.1": "foo", "2.2": 5 }, "1.2": [ 1, 2, true ], "1.3": null }';
+
+      final result = RealmValue.fromJson(json);
+      expect(result.type, RealmValueType.map);
+
+      final o1 = result.asMap()['1.1'];
+      expect(o1, isNotNull);
+      expect(o1!.type, RealmValueType.map);
+      expect(o1.asMap()['2.1']!.value, 'foo');
+      expect(o1.asMap()['2.2']!.value, 5);
+
+      final o2 = result.asMap()['1.2'];
+      expect(o2, isNotNull);
+      expect(o2!.type, RealmValueType.list);
+      expect(o2.asList()[0].value, 1);
+      expect(o2.asList()[1].value, 2);
+      expect(o2.asList()[2].value, true);
+
+      final o3 = result.asMap()['1.3'];
+      expect(o3, isNotNull);
+      expect(o3!.type, RealmValueType.nullValue);
+      expect(o3.value, null);
+    });
+
+    test('Constructs arrays', () {
+      final json = '[ "foo", true, { "foo": "bar" }, [ 1, 2.2, 3 ]]';
+
+      final result = RealmValue.fromJson(json);
+      expect(result.type, RealmValueType.list);
+      expect(result.asList(), hasLength(4));
+      expect(result.asList()[0].value, "foo");
+      expect(result.asList()[1].value, true);
+
+      final map = result.asList()[2];
+      expect(map.type, RealmValueType.map);
+      expect(map.asMap()['foo']!.value, 'bar');
+
+      final list = result.asList()[3];
+      expect(list.type, RealmValueType.list);
+      expect(list.asList(), hasLength(3));
+      expect(list.asList()[0].value, 1);
+      expect(list.asList()[0].type, RealmValueType.int);
+      expect(list.asList()[1].value, 2.2);
+      expect(list.asList()[1].type, RealmValueType.double);
+      expect(list.asList()[2].value, 3);
+      expect(list.asList()[2].type, RealmValueType.int);
+    });
+
+    test('Constructs string', () {
+      final json = '"foo"';
+      final result = RealmValue.fromJson(json);
+
+      expect(result.type, RealmValueType.string);
+      expect(result.value, 'foo');
+    });
+
+    test('Constructs integers', () {
+      final json = '-123';
+      final result = RealmValue.fromJson(json);
+
+      expect(result.type, RealmValueType.int);
+      expect(result.value, -123);
+    });
+
+    test('Constructs doubles', () {
+      final json = '-123.456';
+      final result = RealmValue.fromJson(json);
+
+      expect(result.type, RealmValueType.double);
+      expect(result.value, -123.456);
+    });
+
+    test('Constructs bools', () {
+      final json = 'true';
+      final result = RealmValue.fromJson(json);
+
+      expect(result.type, RealmValueType.boolean);
+      expect(result.value, true);
+    });
+
+    test('Constructs nulls', () {
+      final json = 'null';
+      final result = RealmValue.fromJson(json);
+
+      expect(result.type, RealmValueType.nullValue);
+      expect(result.value, isNull);
+    });
+  });
 }