How to updated the lastly added data to a array of objects in mongo db

Question

Here is my data

{
"userId": "xyzzzz",
"items": [{
    "addedToCartOn": 1536131159,
    "itemName": "Chicken Sausage Pizza (Personal)",
    "sku": "Ch-Pi-No-No-rIotXAkFXe",
    "addOnsAdded": 1,
    "quantity": 1
}, {
    "addedToCartOn": 1536131159,
    "itemName": "Chicken Sausage Pizza (Personal)",
    "sku": "Ch-Pi-No-No-rIotXAkFXe",
    "addOnsAdded": 1,
    "quantity": 1
}]
 }

Now i want to increase the "quantity" of the data which is lastly added to the items array.

Answer 1

You can try this if you know the index of the last item. In this case it is 1

db.collection.update({"userId": "xyzzzz"},{$set:{"items.1.quantity":2}})