Add singleline

Author: martijn00

CHANGELOG.md

@@ -42,6 +42,7 @@
 * Add aggregate
 * Add unique
 * Add ISBN
+* Add singleLine
 
 ## 10.0.1
 * Fix regression (include l10n files)

README.md

@@ -88,6 +88,7 @@ Available built-in type validators include:
 - `FormBuilderValidators.between()` - requires the field's to be between two numbers.
 - `FormBuilderValidators.containsElement()` - requires the field's to be in the provided list.
 - `FormBuilderValidators.unique()` - requires the field's to be unique in the provided list.
+- `FormBuilderValidators.singleLine()` - requires the field's string to be a single line of text.
 
 Available built-in use-case validators include:
 

lib/l10n/intl_en.arb

@@ -53,5 +53,6 @@
   "ibanErrorText": "Value must be a valid IBAN.",
   "uniqueErrorText": "Value must be unique.",
   "bicErrorText": "Value must be a valid BIC.",
-  "isbnErrorText": "Value must be a valid ISBN."
+  "isbnErrorText": "Value must be a valid ISBN.",
+  "singleLineErrorText": "Value must be a single line."
 }

lib/src/form_builder_validators.dart

@@ -1050,4 +1050,14 @@ class FormBuilderValidators {
           valueCandidate?.isEmpty != false || !isISBN(valueCandidate!)
               ? errorText ?? FormBuilderLocalizations.current.isbnErrorText
               : null;
+
+  /// [FormFieldValidator] that requires the field's value to be a single line.
+  /// * [errorText] is the error message to display when the value is not a single line
+  static FormFieldValidator<String> singleLine({
+    String? errorText,
+  }) =>
+      (valueCandidate) => valueCandidate?.isEmpty != false ||
+              !isSingleLine(valueCandidate!)
+          ? errorText ?? FormBuilderLocalizations.current.singleLineErrorText
+          : null;
 }

lib/src/utils/validators.dart

@@ -508,3 +508,7 @@ bool isISBN(String isbn) {
     return false;
   }
 }
+
+bool isSingleLine(String value) {
+  return !value.contains('\n') && !value.contains('\r');
+}

test/form_builder_validators_test.dart

@@ -1186,10 +1186,26 @@ void main() {
       expect(validator('0-306-40615-2'), isNull); // A valid ISBN-10
       // Fail
       expect(validator(null), isNotNull);
-      expect(validator(''), isNotNull); // Empty string
+      expect(validator(''), isNotNull);
       expect(validator('INVALIDISBN'), isNotNull); // Invalid ISBN
       expect(validator('978-3-16-148410-00'), isNotNull); // Too long
       expect(validator('3-16-148410-00'), isNotNull); // Too short
     }),
   );
+
+  testWidgets(
+    'FormBuilderValidators.singleLine',
+    (WidgetTester tester) => testValidations(tester, (context) {
+      final validator = FormBuilderValidators.singleLine();
+      // Pass
+      expect(validator('The quick brown fox jumps'), isNull);
+      // Fail
+      expect(validator(null), isNotNull);
+      expect(validator(''), isNotNull);
+      expect(validator('The quick brown fox\njumps'), isNotNull);
+      expect(validator('The quick brown fox\rjumps'), isNotNull);
+      expect(validator('The quick brown fox\r\njumps'), isNotNull);
+      expect(validator('The quick brown fox\n\rjumps'), isNotNull);
+    }),
+  );
 }