firebase - Add map if it dosen't exist else increase quantity if it exists in the array

Question

I have a list/collection and I need to check if a product exist by the same id, I need to increase the quantity else add the product. I am able to add product if id dosen't exist but I am not able to increase quanity if the product dosen't exist.

cart_items = [
        {
            "id": 144,
            "created_at": "2019-04-04 14:42:04",
            "updated_at": "2019-04-04 14:42:04",
            "cart_id": "3",
            "client_id": "83",
            "product_id": "6",
            "quantity": "1",
            "price": "1500",
            "name": "Cucumber (2Pcs)",
            "image": "products/es4eGjkgQ6MvzTaMyX4iXWjcSX03mVk3QB9oODWk.jpeg",
           },
        {
            "id": 145,
            "created_at": "2019-04-04 14:42:09",
            "updated_at": "2019-04-04 14:42:09",
            "cart_id": "3",
            "client_id": "83",
            "product_id": "5",
            "quantity": "1",
            "price": "2000",
            "name": "Cauliflower",
            "image": "products/lVZ31zORzltyVIDXhHoCWUgjTlal7cWd7pI8DL2V.jpeg",
            }
    ]

Edit:

I have implemented this till now:

if (snapshot.data.data()["Array"][0]["id"] == 1489) {
                  FirebaseFirestore.instance
                      .collection("text")
                      .doc("qjxuj18kfcOpqBVLWjVD")
                      .update({
                    'Array': FieldValue.arrayUnion(
                      [
                        {
                          "id": 14999,
                          "created_at": "2019-04-04 14:42:09",
                          "updated_at": "2019-04-04 14:42:09",
                          "cart_id": "3",
                          "client_id": "83",
                          "product_id": "5",
                          "quantity": 1,
                          "price": "2000",
                          "name": "Cauliflower",
                          "image":
                              "products/lVZ31zORzltyVIDXhHoCWUgjTlal7cWd7pI8DL2V.jpeg",
                        }
                      ],
                    ),
                  });
                } else {
                  print(snapshot.data.data()["Array"][0]["id"]);
                  FirebaseFirestore.instance
                      .collection("test")
                      .doc("qjxuj18kfcOpqBVLWjVD")
                      .update(
                    {
                      'Array'[0]["id"]: 
                    },
                  );
                }

I am using Fieldvalue.ArrayUnion to check if a value exist, now I want to implement Fieldvalue.increment() . Reason: updating and uploading the whole array is not convinent . Everything is working fine but getting stuck at the else part ...

Thank you in advance.

question from:https://stackoverflow.com/questions/65876045/add-map-if-it-dosent-exist-else-increase-quantity-if-it-exists-in-the-array

Answer 1

This function should do the trick:

def add_item(local_cart_items, my_item):
    for item in local_cart_items:
        if item["id"] == my_item["id"]: #If item is in the shopping cart increase the 'quantity'
            item["quantity"] = str(int(item["quantity"]) + 1)
            return

    #If item is not in the shopping cart just add it
    local_cart_items.append(my_item)

• It takes 2 arguments, the whole cart_items and an item.
• It checks the ID of each item in the list and matches it against the given item.
• If it finds a match: function increases the quantity attribute.
• If it doesn't find a match: function inserts the item into the cart_items.