computeItemsPerPageOptions method
Implementation
List<int> computeItemsPerPageOptions(List<int> options) {
if (totalItems == 0) return options.where((x) => x > 0).toList()..sort();
final optionsSet = <int>{computedItemsPerPage, ...options};
return optionsSet.where((x) => x <= totalItems && x > 0).toList()..sort();
}