validateCity method

String? Function(String?) validateCity(
  1. String? value, {
  2. String? requiredError,
  3. String? invalidError,
})

Implementation

String? Function(String?) validateCity(String? value,
    {String? requiredError, String? invalidError}) {
  return (String? value) {
    if (value == null || value.isEmpty) {
      return requiredError ?? 'Please enter a city';
    }

    // Regular expression to validate city format
    final cityRegex = RegExp(r'^[a-zA-Z ]+$');
    if (!cityRegex.hasMatch(value)) {
      return invalidError ?? 'Please enter a valid city';
    }

    return null; // Return null to indicate valid input
  };
}