fix: Deep-copy arrays correctly

lib/src/utils/map_copy_extension.dart

@@ -22,16 +22,25 @@
 */
 
 extension MapCopyExtension on Map<String, dynamic> {
+  dynamic _copyValue(dynamic value) {
+    if (value is Map<String, dynamic>) {
+      return value.copy();
+    }
+    if (value is List) {
+      final ret = [];
+      for (final val in value) {
+        ret.add(_copyValue(val));
+      }
+      return ret;
+    }
+    return value;
+  }
+
   /// Deep-copies a given json map
   Map<String, dynamic> copy() {
     final copy = Map<String, dynamic>.from(this);
     for (final entry in copy.entries) {
-      if (entry.value is Map<String, dynamic>) {
-        copy[entry.key] = (entry.value as Map<String, dynamic>).copy();
-      }
-      if (entry.value is List) {
-        copy[entry.key] = List.from(entry.value);
-      }
+      copy[entry.key] = _copyValue(entry.value);
     }
     return copy;
   }

test/map_copy_extension_test.dart

@@ -40,5 +40,18 @@ void main() {
       original['child']['list'].add(3);
       expect(copy['child']['list'], [1, 2]);
     });
+    test('should do arrays', () {
+      final original = <String, dynamic>{
+        'arr': [
+          [1, 2],
+          {'beep': 'boop'},
+        ],
+      };
+      final copy = original.copy();
+      original['arr'][0].add(3);
+      expect(copy['arr'][0], [1, 2]);
+      original['arr'][1]['beep'] = 'blargh';
+      expect(copy['arr'][1]['beep'], 'boop');
+    });
   });
 }