v1.4.8: Add recursive JSON-safe serialization utilities

- Introduced extension methods for recursive serialization and deserialization of nested maps/lists: `toJsonValue()`, `fromJsonValue()`, `toJsonMap()`, `fromJsonMap()`, `toJsonList()`, and `fromJsonList()`.
- Updated README.md to include new utilities.
- Added tests for JSON value extensions.
- Bumped version to 1.4.8.

Signed-off-by: Hans Kokx <hans.d.kokx@gmail.com>

lib/arcane_helper_utils.dart

@@ -3,6 +3,7 @@ library arcane_helper_utils;
 export "package:arcane_helper_utils/src/classes/fixed_size_list.dart";
 export "package:arcane_helper_utils/src/extensions/date_time.dart";
 export "package:arcane_helper_utils/src/extensions/dynamic.dart";
+export "package:arcane_helper_utils/src/extensions/json_value.dart";
 export "package:arcane_helper_utils/src/extensions/jwt.dart";
 export "package:arcane_helper_utils/src/extensions/list.dart";
 export "package:arcane_helper_utils/src/extensions/string.dart";

lib/src/extensions/json_value.dart

@@ -0,0 +1,64 @@
+/// Extension methods for recursively serializing and deserializing JSON-like
+/// values.
+extension JsonValueObjectExtension on Object? {
+  /// Recursively serializes this value into a JSON-safe value.
+  Object? toJsonValue() => _JsonValueHelper._toJsonValue(this);
+
+  /// Recursively deserializes this JSON-like value into nested Dart values.
+  Object? fromJsonValue() => _JsonValueHelper._fromJsonValue(this);
+
+  /// Recursively deserializes this JSON-like value into a map.
+  ///
+  /// Returns `null` when this value is `null` or not a map.
+  Map<String, Object?>? fromJsonMap() => _JsonValueHelper._fromJsonMap(this);
+}
+
+/// Extension methods for JSON map serialization.
+extension JsonValueMapExtension on Map<Object?, Object?> {
+  /// Recursively serializes this map into a JSON-safe map with string keys.
+  Map<String, Object?> toJsonMap() => _JsonValueHelper._toJsonMap(this);
+}
+
+/// Extension methods for JSON list serialization and deserialization.
+extension JsonValueListExtension on List<Object?> {
+  /// Recursively serializes this list into a JSON-safe list.
+  List<Object?> toJsonList() => _JsonValueHelper._toJsonList(this);
+
+  /// Recursively deserializes this JSON-like list into nested Dart values.
+  List<Object?> fromJsonList() => _JsonValueHelper._fromJsonList(this);
+}
+
+abstract class _JsonValueHelper {
+  static Object? _toJsonValue(Object? value) {
+    if (value == null) return null;
+    if (value is String || value is num || value is bool) return value;
+    if (value is Map) return _toJsonMap(value);
+    if (value is List) return _toJsonList(value.cast<Object?>());
+    return value.toString();
+  }
+
+  static Map<String, Object?> _toJsonMap(Map<Object?, Object?> map) {
+    return map.map((k, v) => MapEntry(k.toString(), _toJsonValue(v)));
+  }
+
+  static List<Object?> _toJsonList(List<Object?> list) {
+    return list.map(_toJsonValue).toList();
+  }
+
+  static Object? _fromJsonValue(Object? value) {
+    if (value == null) return null;
+    if (value is Map) return _fromJsonMap(value);
+    if (value is List) return _fromJsonList(value.cast<Object?>());
+    return value;
+  }
+
+  static Map<String, Object?>? _fromJsonMap(Object? value) {
+    if (value == null) return null;
+    if (value is! Map) return null;
+    return value.map((k, v) => MapEntry(k.toString(), _fromJsonValue(v)));
+  }
+
+  static List<Object?> _fromJsonList(List<Object?> list) {
+    return list.map(_fromJsonValue).toList();
+  }
+}

lib/src/extensions/jwt.dart

@@ -1,6 +1,6 @@
 import "dart:convert";
 
-typedef JwtPayload = Map<String, dynamic>;
+typedef JwtPayload = Map<String, Object?>;
 
 /// An extension on `String` to extract useful information from JSON Web Tokens (JWT).
 ///