summary_report.rb

      function(doc, prev) { 
        prev.check_count   += 1;
        prev.total         += doc.total;
        prev.tax           += doc.tax;
        prev.subtotal      += doc.subtotal;
        prev.payment       += doc.payment;
        prev.tender        += doc.tender;
        prev.discount      += doc.discount;
        prev.coupon        += doc.coupon;

        if (doc.receipts) { 
          prev.receipt_count += doc.receipts.length;

          doc.receipts.forEach(function(receipt) {
            if (receipt.receipt_items) {
              prev.item_count += receipt.receipt_items.length;
            }

            if (receipt.receipt_messages) {
              prev.message_count += receipt.receipt_messages.length;
            }
          });
        }
      }