pattern static method

FormFieldValidator pattern(String pattern, { String errorText = "Value does not match pattern.", })

FormFieldValidator that requires the field's value to match the provided regex pattern.

Implementation

static FormFieldValidator pattern(
  String pattern, {
  String errorText = "Value does not match pattern.",
}) {
  final regex = RegExp(pattern);
  return (valueCandidate) {
    if (valueCandidate is String && valueCandidate.isNotEmpty) {
      if (!regex.hasMatch(valueCandidate)) {
        return errorText;
      }
    }
    return null;
  };
}