pattern method
FormFieldValidator
that requires the field's value to match the provided regex pattern.
Implementation
static FormFieldValidator pattern(
Pattern pattern, {
String errorText = "Value does not match pattern.",
}) {
return (valueCandidate) {
if (valueCandidate != null && valueCandidate.isNotEmpty) {
if (!RegExp(pattern).hasMatch(valueCandidate)) return errorText;
}
return null;
};
}