Changing from Firebase to Firestore caused Fatal error: Unexpectedly found nil ... in a query - swift

Question

I am trying to retrieve a user's data from firestore, after migrating my data there from firebase. The code below was working fine with firebase, and retrieved the user's data.
However, after changing the query to firestore query, I got this error.
Print statement here "document.data()" contains the data, But I got this error. I don't know where this error is coming from.
When I compare document.data() with nil, I got "Document data: contains nil".
I don't know how I suppoused to get the data.
here is the code where I get the error,
static func getUser(uid: String, setUserDefaults: #escaping (NormalUser) -> Void){
DataService.ds.REF_USERS_NORMAL.document(uid).getDocument { (document, error) in
if error != nil{
print("\(String(describing: error?.localizedDescription))")
}else{
if document != nil{
let data = document?.data() as! [String: String]
print("Document data: \(String(describing: document?.data() as! [String: String]))")
let user = NormalUser(userData: (data as Dictionary<String, AnyObject>))
setUserDefaults(user)
}else{
print("Document data: contains nil")
}
}
}
}
Here is how I defined the variables,
import Foundation
import Firebase
class NormalUser: User {
private var _email: String?
private var _city: String?
private var _country: String?
private var _name: String?
private var _phone: String?
private var _profileImgUrl: String?
var email: String {
return _email!
}
var city: String {
return _city!
}
var country: String {
return _country!
}
var name: String {
return _name!
}
var phone: String {
return _phone!
}
var profileImgUrl: String {
set{
self.profileImgUrl = _profileImgUrl!
}
get{
if let pI = _profileImgUrl{
return pI
}
return ""
}
}
init(userData: Dictionary<String, AnyObject>) {
super.init(userId: userData["uid"] as! String, user: userData)
if let email = userData["email"] as? String {
self._email = email
}
if let city = userData["city"] as? String {
self._city = city
}
if let country = userData["country"] as? String {
self._country = country
}
if let name = userData["name"] as? String {
self._name = name
}
if let phone = userData["phone"] as? String {
self._phone = phone
}
if let profileImgUrl = userData["imgUrl"] as? String {
self._profileImgUrl = profileImgUrl
}
}
static func createNormalUser(uid: String, userData: Dictionary<String, String>) {
// add user to database
//DataService.ds.REF_USERS_NORMAL.child(uid).setValue(userData)
DataService.ds.REF_USERS_NORMAL.document(uid).setData(userData) { (err) in
if let err = err {
print("Error writing document: \(err)")
} else {
print("Document successfully written!")
}
}
addUserToGroup(uid:uid, group:"normal")
}
static func updateUserProfile(uid: String, userData: Dictionary<String, String>) {
//DataService.ds.REF_USERS_NORMAL.child(uid).updateChildValues(userData)
DataService.ds.REF_USERS_NORMAL.document(uid).updateData(userData)
}
static func getUser(uid: String, setUserDefaults: #escaping (NormalUser) -> Void){
DataService.ds.REF_USERS_NORMAL.document(uid).getDocument { (document, error) in
if error != nil{
print("\(String(describing: error?.localizedDescription))")
}else{
if document != nil{
let data = document?.data() as! [String: String]
print("Document data: \(String(describing: document?.data() as! [String: String]))")
let user = NormalUser(userData: (data as Dictionary<String, AnyObject>))
setUserDefaults(user)
}else{
print("Document data: contains nil")
}
}
}
}
}

Answer 1

I solved the issue!
For any one who may come across this error, the problem was with userId. I was getting the user id from firebase, which, in my case, no longer serves my query, and eventually getting a nil. When I got the ID directly from authentication,
let userID = Auth.auth().currentUser?.uid
It SOLVED the issue!