pattern method

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

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

Implementation

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