loadPage method

Implementation

Future loadPage({PageKeyType? nextPageKey, bool isRefresh = false}) async {
  List<ItemType>? items;

  if (_pagingState is PagingStateData<PageKeyType, ItemType>) {
    items = (_pagingState as PagingStateData<PageKeyType, ItemType>).items;
  }

  await dataSource.loadPage(isRefresh: isRefresh, newKey: nextPageKey).then(
      (value) {
    int? itemCount = isRefresh
        ? [...value].length
        : items != null
            ? [...items, ...value].length
            : [...value].length;

    bool hasNextPage = dataSource.currentKey != null && !dataSource.isEndList;

    bool hasItems = itemCount > 0;

    bool isListingUnfinished = hasItems && hasNextPage;

    bool isOngoing = isListingUnfinished;

    // bool isCompleted = hasItems && !hasNextPage;

    /// The current pagination status.
    PagingStatus status =
        (isOngoing) ? PagingStatus.ongoing : PagingStatus.completed;

    emit(PagingState<PageKeyType, ItemType>(
        isRefresh
            ? [...value]
            : items != null
                ? [...items, ...value]
                : [...value],
        status,
        false));
  }, onError: (e) {
    if (dataSource.currentKey == null) {
      emit(PagingState<PageKeyType, ItemType>.error(e));
    } else {
      if (_pagingState is PagingStateData<PageKeyType, ItemType>) {
        final stateData =
            _pagingState as PagingStateData<PageKeyType, ItemType>;
        emit(PagingState<PageKeyType, ItemType>(
            stateData.items, PagingStatus.noItemsFound, true));
      }
    }
  });
}