validateZip method

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

Implementation

String? validateZip(String? value,
    {String? requiredError, String? invalidError}) {
  if (value == null || value.isEmpty) {
    return requiredError ?? 'Please enter a ZIP code';
  }

  // Regular expression to validate ZIP code format
  final zipRegex = RegExp(r'^[0-9]+$');
  if (!zipRegex.hasMatch(value)) {
    return invalidError ?? 'Please enter a valid ZIP code';
  }

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