toCommaAndList method

Implementation

String toCommaAndList() {
  if (length == 0) {
    return "";
  } else if (length == 1) {
    return first;
  } else if (length == 2) {
    return "${this[0]} and ${this[1]}";
  } else {
    final tempCopy = List.of(this);
    tempCopy[length - 1]  = "and $last";
    return tempCopy.join(", ");
  }
}