public sellerId$ = this._route.params
      .map((params: IRouteParams) => params.id)
      .take(1)

  public noPending$ = this.pending$
    .map(pendingOperations => pendingOperations
      .map(pending => pending.reason)
      .some(reason => GetSellerAction.isInstance(reason) || GetPricesAction.isInstance(reason))
    )
    .map(hasPending => !hasPending)

  public totalPages$: Observable<number> = this.nonEmptySeller$
    .map(seller => seller.totalItemsCount)
    .map(count => count / this.itemsPerPage)
    .map(Math.ceil)

  public footerCountries$: Observable<OrderedMap<string, IUrl>> = this.sellerId$
    .map(id => this._getCountryOptions(id))