Add some

Author: martijn00

CHANGELOG.md

@@ -34,6 +34,10 @@
 * Add contains
 * Add between
 * Add inList
+* Add transform
+* Add debounce
+* Add retry
+
 
 ## 10.0.1
 * Fix regression (include l10n files)

README.md

@@ -51,6 +51,9 @@ Available built-in helper validators:
 - `FormBuilderValidators.compose()` - runs each validator against the value provided.
 - `FormBuilderValidators.conditional()` - conditionally runs a validator against the value provided.
 - `FormBuilderValidators.or()` - runs each validator against the value provided and passes when any works.
+- `FormBuilderValidators.transform()` - transforms the value before running the validator.
+- `FormBuilderValidators.debounce()` - runs the validator after a set time.
+- `FormBuilderValidators.retry()` - runs the validator again after failing while waiting a certain time.
 
 Available built-in type validators include:
 

lib/src/form_builder_validators.dart

@@ -1,3 +1,5 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import '../form_builder_validators.dart';
 
@@ -43,6 +45,62 @@ class FormBuilderValidators {
     };
   }
 
+  /// [FormFieldValidator] that transforms the value before applying the validator.
+  static FormFieldValidator transform<T>(
+    FormFieldValidator<T> validator,
+    T Function(T? value) transformer,
+  ) {
+    return (valueCandidate) {
+      final transformedValue = transformer(valueCandidate);
+      return validator(transformedValue);
+    };
+  }
+
+  /// [FormFieldValidator] that debounces the validation.
+  /// * [duration] is the duration to wait before running the validation.
+  static FormFieldValidator<T> debounce<T>({
+    required Duration duration,
+    required FormFieldValidator<T> validator,
+  }) {
+    Timer? debounceTimer;
+    String? result;
+
+    return (valueCandidate) {
+      debounceTimer?.cancel();
+      debounceTimer = Timer(duration, () {
+        result = validator(valueCandidate);
+      });
+
+      return result;
+    };
+  }
+
+  /// [FormFieldValidator] that retries the validation.
+  /// * [times] is the number of times to retry the validation.
+  /// * [duration] is the duration to wait before retrying the validation.
+  static FormFieldValidator<T> retry<T>({
+    required int times,
+    required Duration duration,
+    required FormFieldValidator<T> validator,
+  }) {
+    int retries = 0;
+    String? result;
+
+    return (valueCandidate) {
+      if (retries < times) {
+        result = validator(valueCandidate);
+        if (result != null) {
+          retries++;
+          Future.delayed(duration, () {
+            result = validator(valueCandidate);
+          });
+        }
+      }
+
+      return result;
+    };
+  }
+
   /// [FormFieldValidator] that requires the field have a non-empty value.
   static FormFieldValidator<T> required<T>({
     String? errorText,