var list_items = [];
            var orders = this.pos.get('orders').models;
            if (orders.length > 0) {
                for (let i = 0; i < orders.length; i++) {
                    let order = orders[i].orderlines.models;
                    if (order.length > 0) {
                        for (let j = 0; j < order.length; j++) {
                            let orderline = order[j];
                            list_items.push(orderline);
                        }
                    }
                }
            }