paginate method

void paginate({ required PagedQueryExecutor<R> executor, })

Implementation

void paginate({
  required PagedQueryExecutor<R> executor,
}) async {
  /// showing loading with other contents intact.
  emit(state.copyWith(status: PagedStatus.loading));

  if (state.status == PagedStatus.end) emit(state);

  /// This is inner function
  Future<QuerySnapshot<R>> fetch(DocumentSnapshot<R>? skip) async {
    final result = await executor(skip);
    return result;
  }

  try {
    if (state.status == PagedStatus.initial) {
      final result = await fetch(null);

      final items = result.docs.map((e) {
        return FireData(object: e.data(), doc: e);
      }).toList();

      emit(
        state.copyWith(
          status: _hasReachedEnd(items.length),
          items: items,
        ),
      );
    }

    if (state.items.isNotEmpty) {
      final last = state.items.last.doc;

      final result = await fetch(last);

      final items = result.docs.map((e) {
        return FireData(object: e.data(), doc: e);
      }).toList();

      if (items.isEmpty) {
        emit(state.copyWith(status: PagedStatus.end));
      } else {
        emit(state.copyWith(
          status: _hasReachedEnd(items.length),
          items: List.of(state.items)..addAll(items),
        ));
      }
    } else {
      emit(state.copyWith(status: PagedStatus.end));
    }
  } catch (e) {
    emit(state.copyWith(
      status: PagedStatus.failure,
      message: e.toString(),
    ));
  }
}