Swift/FireStore - Appending/updating elements in an array

Question

Ok, so this feature is semi-working:

API.FIRESTORE_DOCUMENT_USERID(userID: userID).updateData(["user_rating":FieldValue.arrayUnion([averageRating])])

As you can tell, I'm trying to update the user_rating field and pass in the average rating. However, since the average rating can be anywhere from 1-5, including decimals/doubles, there is a likelihood that the average rating will already exist i.e. 1.5, 2.5, 2.7 etc. However, I cannot seem too append the same value twice. If I change the rating, then sure I can append. As far as I'm aware, each entry in an array has it's own ID? Any way I can allow for duplicates?

Thank you.

Answer 1

Found the solution, you must first read the existing data in the array, then append whatever data you wish then once again update the data, like so:

[YOUR_REFERENCE].getDocument { (querySnapshot, error) in
                if let error = error {
                    print(error.localizedDescription)
                } else {
                    var array:[THE_DATA_TYPE] = querySnapshot?.get("[FIELD_NAME]") as [THE_DATA_TYPE]
                    array.append([DATA_YOU_WISH_TO_APPEND])
                    querySnapshot?.reference.updateData(["[FIELD_NAME]" : array])
                }
            }

I've made it generic in the event anyone ever just wishes to copy and paste.