Getting incorrect value form firebase in swift - ios

Question

This is my code
let db = Firestore.firestore()
db.collection("chats").document(userDefaults.string(forKey: "currentGroup")!).collection("messages").document("variable").addSnapshotListener { (snapshot, error) in
if error != nil{
print("Error fetching document")
}
else{
let documentData = snapshot!.data()
print(documentData!["numOfMessages"])
self.numOfMessages = documentData!["numOfMessages"] as! Int
print(self.numOfMessages)
//Get texts and display them
db.collection("chats").document(self.userDefaults.string(forKey: "currentGroup")!).collection("messages").document("\(self.numOfMessages)").getDocument { (document, err) in
let newMessageData = document!.data()
let newMessage = newMessageData!["message"] as! String
let newAuthor = newMessageData!["author"] as! String
let authorLabel = UILabel()
authorLabel.text = newAuthor
self.stackView.addArrangedSubview(authorLabel)
let label = UILabel()
label.text = newMessage
self.stackView.addArrangedSubview(label)
}
}
}
This line self.numOfMessages = documentData!["numOfMessages"] as! Int has an error of
Could not cast value of type 'NSTaggedPointerString' (0x1ed6ed450) to 'NSNumber' (0x1ed6f98c8).
This is every since I deleted the collection messages and replaced it with one of the exact same name
The value that documentData!["numOfMessages"] returns is Optional(1) even though in firebase the value is 2.
This is how the Firestore looks:

Answer 1

Either you are listening to the wrong document (perhaps because of an incorrect user default) or you are unwrapping the value incorrectly. To debug this, try the following and see what the problem actually is. The following is a more idiomatic way of handling documents.
if let currentGroup = userDefaults.string(forKey: "currentGroup") {
print(currentGroup) // this could be your problem
Firestore.firestore().collection("chats").document(currentGroup).collection("messages").document("variable").addSnapshotListener { (snapshot, error) in
if let snapshot = snapshot {
if let numOfMessages = snapshot.get("numOfMessages") as? Int {
print(numOfMessages)
} else {
print("field error")
}
} else if let error = error {
print(error)
}
}
} else {
print("no current group")
}