feat(validator): add PhoneValidator helper

lib/phone_form_field.dart

@@ -1,14 +1,15 @@
 library phone_number_input;
 
-export 'src/widgets/phone_form_field.dart';
-export 'src/widgets/base_phone_form_field.dart';
-
-export 'src/models/selector_config.dart';
-export 'src/widgets/country_picker/country_selector.dart';
-export 'src/widgets/flag_dial_code_chip.dart';
-export 'src/localization/phone_field_localization.dart';
 export 'package:phone_numbers_parser/phone_numbers_parser.dart'
     show PhoneNumber, PhoneNumberType, PhoneParser, LightPhoneParser;
+
+export 'src/localization/phone_field_localization.dart';
+export 'src/models/all_countries.dart';
 export 'src/models/country.dart';
+export 'src/models/selector_config.dart';
+export 'src/validator/phone_validator.dart';
+export 'src/widgets/base_phone_form_field.dart';
+export 'src/widgets/country_picker/country_selector.dart';
 export 'src/widgets/country_picker/country_selector_navigator.dart';
-export 'src/models/all_countries.dart';
+export 'src/widgets/flag_dial_code_chip.dart';
+export 'src/widgets/phone_form_field.dart';

lib/src/validator/phone_validator.dart

@@ -0,0 +1,92 @@
+import 'package:dart_countries/dart_countries.dart';
+import 'package:flutter/widgets.dart';
+import 'package:phone_form_field/phone_form_field.dart';
+
+typedef PhoneNumberInputValidator = String? Function(PhoneNumber? phoneNumber);
+
+class PhoneValidator {
+  static PhoneNumberInputValidator compose(
+      List<PhoneNumberInputValidator> validators) {
+    return (valueCandidate) {
+      for (var validator in validators) {
+        final validatorResult = validator.call(valueCandidate);
+        if (validatorResult != null) {
+          return validatorResult;
+        }
+      }
+      return null;
+    };
+  }
+
+  static PhoneNumberInputValidator required<T>(
+    BuildContext context, {
+    String? errorText,
+  }) {
+    final defaultMessage = "Phone number required";
+    return (PhoneNumber? valueCandidate) {
+      if (valueCandidate == null || (valueCandidate.nsn.trim().isEmpty)) {
+        return errorText ??
+            PhoneFieldLocalization.of(context)?.translate(defaultMessage) ??
+            defaultMessage;
+      }
+      return null;
+    };
+  }
+
+  static PhoneNumberInputValidator invalid(
+    BuildContext context, {
+    String? errorText,
+    bool useLightParser = false,
+  }) {
+    final defaultMessage = "Phone number invalid";
+    final parser = useLightParser ? LightPhoneParser() : PhoneParser();
+    return (PhoneNumber? valueCandidate) {
+      if (valueCandidate == null || !parser.validate(valueCandidate)) {
+        return errorText ??
+            PhoneFieldLocalization.of(context)?.translate(defaultMessage) ??
+            defaultMessage;
+      }
+      return null;
+    };
+  }
+
+  static PhoneNumberInputValidator type(
+    BuildContext context,
+    PhoneNumberType expectedType, {
+    String? errorText,
+    bool useLightParser = false,
+  }) {
+    final defaultMessage = expectedType == PhoneNumberType.mobile
+        ? "Invalid mobile phone number"
+        : "Invalid landline phone number";
+    final parser = useLightParser ? LightPhoneParser() : PhoneParser();
+    return (PhoneNumber? valueCandidate) {
+      if (valueCandidate == null ||
+          !parser.validate(valueCandidate, expectedType)) {
+        return errorText ??
+            PhoneFieldLocalization.of(context)?.translate(defaultMessage) ??
+            defaultMessage;
+      }
+      return null;
+    };
+  }
+
+  static PhoneNumberInputValidator country(
+    BuildContext context,
+    List<String> expectedCountries, {
+    String? errorText,
+  }) {
+    assert(expectedCountries.every((isoCode) => isoCodes.contains(isoCode)),
+        'Each expectedCountries value be valid country isoCode');
+    final defaultMessage = "Invalid country";
+    return (PhoneNumber? valueCandidate) {
+      if (valueCandidate == null ||
+          !expectedCountries.contains(valueCandidate.isoCode)) {
+        return errorText ??
+            PhoneFieldLocalization.of(context)?.translate(defaultMessage) ??
+            defaultMessage;
+      }
+      return null;
+    };
+  }
+}

lib/src/widgets/base_phone_form_field.dart

@@ -1,7 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/services.dart';
-import 'package:phone_form_field/src/localization/phone_field_localization.dart';
 import 'package:phone_form_field/src/models/phone_number_input.dart';
 
 import '../models/country.dart';
@@ -206,7 +205,7 @@ class _BasePhoneFormFieldState extends FormFieldState<PhoneNumberInput> {
 
   InputDecoration _getEffectiveDecoration() {
     return widget.decoration.copyWith(
-      errorText: getErrorText(),
+      errorText: errorText,
       prefix: _getDialCodeChip(),
     );
   }
@@ -222,11 +221,4 @@ class _BasePhoneFormFieldState extends FormFieldState<PhoneNumberInput> {
       ),
     );
   }
-
-  // // which error text to show
-  String? getErrorText() {
-    if (errorText != null) {
-      return PhoneFieldLocalization.of(context)?.translate(errorText!);
-    }
-  }
 }

test/phone_validator_test.dart

@@ -0,0 +1,140 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:phone_form_field/phone_form_field.dart';
+import 'package:phone_form_field/src/validator/phone_validator.dart';
+
+void main() async {
+  Future<BuildContext> getBuildContext(WidgetTester tester) async {
+    await tester.pumpWidget(MaterialApp(home: Material(child: Container())));
+    return tester.element(find.byType(Container));
+  }
+
+  group('PhoneValidator.compose', () {
+    testWidgets('compose should test each validator until first failure',
+        (WidgetTester tester) async {
+      bool firstValidationDone = false;
+      bool lastValidationDone = false;
+      final validator = PhoneValidator.compose([
+        (PhoneNumber? p) {
+          firstValidationDone = true;
+        },
+        (PhoneNumber? p) {
+          return "validation failed";
+        },
+        (PhoneNumber? p) {
+          lastValidationDone = true;
+        },
+      ]);
+      expect(validator(PhoneNumber(isoCode: '', nsn: '')),
+          equals("validation failed"));
+      expect(firstValidationDone, isTrue);
+      expect(lastValidationDone, isFalse);
+    });
+  });
+
+  group('PhoneValidator.required', () {
+    testWidgets('should be required value', (WidgetTester tester) async {
+      final context = await getBuildContext(tester);
+
+      final validator = PhoneValidator.required(context);
+      expect(
+        validator(PhoneNumber(isoCode: 'US', nsn: '')),
+        equals("Phone number required"),
+      );
+
+      final validatorWithText = PhoneValidator.required(
+        context,
+        errorText: 'custom message',
+      );
+      expect(
+        validatorWithText(PhoneNumber(isoCode: 'US', nsn: '')),
+        equals("custom message"),
+      );
+    });
+  });
+
+  group('PhoneValidator.invalid', () {
+    testWidgets('should be invalid', (WidgetTester tester) async {
+      final context = await getBuildContext(tester);
+
+      final validator = PhoneValidator.invalid(context);
+      expect(
+        validator(PhoneNumber(isoCode: 'FR', nsn: '123')),
+        equals("Phone number invalid"),
+      );
+
+      final validatorWithText = PhoneValidator.invalid(
+        context,
+        errorText: 'custom message',
+      );
+      expect(
+        validatorWithText(PhoneNumber(isoCode: 'FR', nsn: '123')),
+        equals("custom message"),
+      );
+    });
+  });
+
+  group('PhoneValidator.type', () {
+    testWidgets('should be invalid mobile type', (WidgetTester tester) async {
+      final context = await getBuildContext(tester);
+
+      final validator = PhoneValidator.type(context, PhoneNumberType.mobile);
+      expect(
+        validator(PhoneNumber(isoCode: 'FR', nsn: '412345678')),
+        equals("Invalid mobile phone number"),
+      );
+
+      final validatorWithText = PhoneValidator.type(
+        context,
+        PhoneNumberType.mobile,
+        errorText: 'custom type message',
+      );
+      expect(
+        validatorWithText(PhoneNumber(isoCode: 'FR', nsn: '412345678')),
+        equals("custom type message"),
+      );
+    });
+
+    testWidgets('should be invalid landline type', (WidgetTester tester) async {
+      final context = await getBuildContext(tester);
+
+      final validator = PhoneValidator.type(context, PhoneNumberType.fixedLine);
+      expect(
+        validator(PhoneNumber(isoCode: 'FR', nsn: '612345678')),
+        equals("Invalid landline phone number"),
+      );
+
+      final validatorWithText = PhoneValidator.type(
+        context,
+        PhoneNumberType.fixedLine,
+        errorText: 'custom fixed type message',
+      );
+      expect(
+        validatorWithText(PhoneNumber(isoCode: 'FR', nsn: '612345678')),
+        equals("custom fixed type message"),
+      );
+    });
+  });
+
+  group('PhoneValidator.country', () {
+    testWidgets('should be invalid country', (WidgetTester tester) async {
+      final context = await getBuildContext(tester);
+
+      final validator = PhoneValidator.country(context, ['FR', 'BE']);
+      expect(
+        validator(PhoneNumber(isoCode: 'US', nsn: '')),
+        equals("Invalid country"),
+      );
+    });
+
+    testWidgets('country validator should refuse invalid isoCode',
+        (WidgetTester tester) async {
+      final context = await getBuildContext(tester);
+
+      expect(
+        () => PhoneValidator.country(context, ['INVALID_ISO_CODE']),
+        throwsAssertionError,
+      );
+    });
+  });
+}