How can I delete a Firestore field, using whereField? - ios

Question

I'm trying to delete a field within a document, when the field "uid" matches the Current User's ID. I'm pretty stuck on this, and would appreciate any help. I detail, below, my code and how my database is set up.
#IBAction func deleteAccountButtonIsTapped(_ sender: Any) {
let db = Firestore.firestore()
let userID = Auth.auth().currentUser?.uid
let username = usernameTextField.placeholder
Auth.auth().currentUser?.delete(completion: { (error) in
if error != nil {
print("ERROR MAIN SETTINGS 136")
} else {
db.collection("FollowerList").whereField("uid", isEqualTo: userID!).getDocuments { (snapshot, error) in
for snapshot in snapshot?.documents {
}
}
}
}
)}
My Database has a collection "FollowerList", with documents named with the User's UID. Within these documents is a "uid" field, with the value of the User's UID.
Any help would be massively appreciated.

Answer 1

This should do the Job:
func deleteAccountButtonIsTapped(_ sender: Any) {
let db = Firestore.firestore()
let userID = Auth.auth().currentUser?.uid
let username = usernameTextField.placeholder
Auth.auth().currentUser?.delete(completion: { (error) in
if error != nil {
print("ERROR MAIN SETTINGS 136")
} else {
db.collection("FollowerList").whereField("uid", isEqualTo: userID!).getDocuments { (snapshot, error) in
if let snapshot = snapshot?.documents {
for doc in snapshot {
//Do delete
db.collection("FollowerList").document(doc.documentID).updateData([
"fieldToDelete": FieldValue.delete(),
]) { err in
if let err = err {
print("Error updating document: \(err)")
} else {
print("Document successfully updated")
}
}
}
}
}
}
}
)}
One would think it could work like this:
But it doesn't as a value of type 'QueryDocumentSnapshot' has no member 'updateData'.
func deleteAccountButtonIsTapped(_ sender: Any) {
let db = Firestore.firestore()
let userID = Auth.auth().currentUser?.uid
let username = usernameTextField.placeholder
Auth.auth().currentUser?.delete(completion: { (error) in
if error != nil {
print("ERROR MAIN SETTINGS 136")
} else {
db.collection("FollowerList").whereField("uid", isEqualTo: userID!).getDocuments { (snapshot, error) in
if let snapshot = snapshot?.documents {
for doc in snapshot {
// How one would think it works but it doesnt
doc.updateData([
"capital": FieldValue.delete(),
]) { err in
if let err = err {
print("Error updating document: \(err)")
} else {
print("Document successfully updated")
}
}
}
}
}
}
}
)}
See this page for further information:
https://firebase.google.com/docs/firestore/manage-data/delete-data#swift