validate499FilerId static method

String? validate499FilerId(
  1. String? value
)

Ensures that a user provides an ID that is 6 digits. TODO: Could query apps.fcc.gov for validation of this field??

Implementation

static String? validate499FilerId(String? value) {
  if (value == null || value.isEmpty) {
    return 'Value can not be empty';
  }

  final regex = RegExp(r'^\d{6}$', caseSensitive: false, multiLine: false);

  if (!regex.hasMatch(value)) {
    return 'Value should be a 6 digit ID';
  }

  return null;
}