fix: support dynamic function callbacks in equal/notEqual validators

CHANGELOG.md

@@ -175,7 +175,7 @@
 
 ## 8.4.0
 
-- Refactor l10n generator. Thanks [@ipcjs]()
+- Refactor l10n generator. Thanks [@ipcjs](https://github.com/ipcjs)
 - Add property to allow empty on equalLength validator. Thanks [@CircleCurve](https://github.com/CircleCurve)
 - Add support for more languages
   - Czech. Thanks [@edlman](https://github.com/flutter-form-builder-ecosystem/form_builder_validators/pull/3)

lib/src/core/equal_validator.dart

@@ -25,12 +25,14 @@ class EqualValidator<T> extends TranslatedValidator<T> {
   /// The value to compare against.
   final Object value;
 
+  Object? get _resolvedValue =>
+      value is Function ? (value as Function)() : value;
+
   @override
-  String get translatedErrorText =>
-      FormBuilderLocalizations.current.equalErrorText(value.toString());
+  String get translatedErrorText => FormBuilderLocalizations.current
+      .equalErrorText(_resolvedValue?.toString() ?? '');
 
   @override
-  String? validateValue(T valueCandidate) {
-    return valueCandidate != value ? errorText : null;
-  }
+  String? validateValue(T valueCandidate) =>
+      valueCandidate != _resolvedValue ? errorText : null;
 }

lib/src/core/not_equal_validator.dart

@@ -25,12 +25,14 @@ class NotEqualValidator<T> extends TranslatedValidator<T> {
   /// The value to compare against.
   final Object value;
 
+  Object? get _resolvedValue =>
+      value is Function ? (value as Function)() : value;
+
   @override
-  String get translatedErrorText =>
-      FormBuilderLocalizations.current.notEqualErrorText(value.toString());
+  String get translatedErrorText => FormBuilderLocalizations.current
+      .notEqualErrorText(_resolvedValue?.toString() ?? '');
 
   @override
-  String? validateValue(T valueCandidate) {
-    return valueCandidate == value ? errorText : null;
-  }
+  String? validateValue(T valueCandidate) =>
+      valueCandidate == _resolvedValue ? errorText : null;
 }

test/src/core/equal_validator_test.dart

@@ -172,5 +172,25 @@ void main() {
         expect(result, customErrorMessage);
       },
     );
+
+    test('should support dynamic function callbacks for comparison value', () {
+      // Arrange
+      String dynamicTarget = 'initial';
+      final EqualValidator<String> validator = EqualValidator<String>(
+        () => dynamicTarget,
+        errorText: customErrorMessage,
+      );
+
+      // Act & Assert 1: Matches initial
+      expect(validator.validate('initial'), isNull);
+      expect(validator.validate('changed'), customErrorMessage);
+
+      // Act: Update dynamicTarget
+      dynamicTarget = 'changed';
+
+      // Act & Assert 2: Now matches changed, not initial
+      expect(validator.validate('changed'), isNull);
+      expect(validator.validate('initial'), customErrorMessage);
+    });
   });
 }

test/src/core/not_equal_validator_test.dart

@@ -180,5 +180,25 @@ void main() {
         );
       },
     );
+
+    test('should support dynamic function callbacks for comparison value', () {
+      // Arrange
+      String dynamicTarget = 'initial';
+      final NotEqualValidator<String> validator = NotEqualValidator<String>(
+        () => dynamicTarget,
+        errorText: customErrorMessage,
+      );
+
+      // Act & Assert 1: Fails matching initial
+      expect(validator.validate('initial'), customErrorMessage);
+      expect(validator.validate('changed'), isNull);
+
+      // Act: Update dynamicTarget
+      dynamicTarget = 'changed';
+
+      // Act & Assert 2: Now fails matching changed, not initial
+      expect(validator.validate('changed'), customErrorMessage);
+      expect(validator.validate('initial'), isNull);
+    });
   });
 }