code: function toLocaleDateTime(date, locales, options, required, defaults, service) {
    if (!(date instanceof GlobalDate)) {
      throw MakeTypeError(kMethodInvokedOnWrongType, "Date");
    }
  
    if (IsNaN(date)) return 'Invalid Date';
  
    var internalOptions = toDateTimeOptions(options, required, defaults);
  
    var dateFormat =
        cachedOrNewService(service, locales, options, internalOptions);
  
    return formatDate(dateFormat, date);
  }
docs: Returns actual formatted date or fails if date parameter is invalid.