Step 10: Remove items with voice

We can also allow users to remove items from the cart with voice.

1. To the dialog script, add a new voice command. This command is similar to the command for adding items, except for sending a negative number with the updateOrder command.

   Dialog script

   intent(`Remove (a|an|) $(ITEM ${itemList}), (please|)`,
          `Remove $(NUMBER) $(ITEM ${itemList}), (please|)`, p => {
       p.play(`Removing ${p.ITEM.value}`, 'No problem', 'Your order is updated');
       let number = p.NUMBER ? p.NUMBER.number : 1;
       p.play({command: 'updateOrder', item: p.ITEM.label, quantity: -number});
   });
   

2. In the app, update the changeOrder() function to the following:

   HTML file

   function changeOrder(item, quantity) {
       let number = (order[item] ? order[item] : 0) + quantity;
       // Removing the item or updating the item quantity
       if (number <= 0) {
           delete order[item];
       } else {
           order[item] = number;
       }
       updateCart();
   }
   

   Web page source | Dialog script

Now, when the number of items is less or equal to 0, the item is removed from the order; otherwise the number for the named position is updated.

In the app, click the Alan AI button and try adding and removing items from the cart with voice.