嵌套Map缺少返回：

private checkDeliveryNotesQuantity(line: SaleLine): Observable<boolean> {
        return this.posSalesTableFacade.getStoreSaleBlockList$().pipe(
          map((saleBlockList: SaleBlock[]) => {
            return saleBlockList.map(saleBlock => {
              return saleBlock.saleLineList.map(saleLineList => {
                console.log('saleLineList', saleLineList);
                return (
                  saleLineList.deliveryNotes &&
                  saleLineList.deliveryNotes.findIndex(
                    item => item.articleId === line.code && item.quantity >= line.missingQuantity
                  ) >= 0
                );
              });
            });
          })
        );
      }

请注意，结果Observable将是Array类型。
为了解决这个问题，您应该从map切换到some

private checkDeliveryNotesQuantity(line: SaleLine): Observable<boolean> {
        return this.posSalesTableFacade.getStoreSaleBlockList$().pipe(
          map((saleBlockList: SaleBlock[]) => {
            return saleBlockList.some(saleBlock => {
              return saleBlock.saleLineList.some(saleLineList => {
                console.log('saleLineList', saleLineList);
                return (
                  saleLineList.deliveryNotes &&
                  saleLineList.deliveryNotes.findIndex(
                    item => item.articleId === line.code && item.quantity >= line.missingQuantity
                  ) >= 0
                );
              });
            });
          })
        );
      }