required method

FormFieldValidator required ({String errorText: "This field cannot be empty." })

FormFieldValidator that requires the field have a non-empty value.

Implementation

static FormFieldValidator required({
  String errorText = "This field cannot be empty.",
}) {
  return (valueCandidate) {
    if (valueCandidate == null ||
        ((valueCandidate is Iterable ||
                valueCandidate is String ||
                valueCandidate is Map) &&
            valueCandidate.length == 0)) {
      return errorText;
    }
  };
}