Trying to access firebase/firestore data in different View Controllers

Hi everyone,

So I’ve been trying to troubleshoot for days now but I can’t seem to find a solution and would love some help!

I originally followed Chris’ “Firebase Authentication Tutorial 2020 - Custom iOS Login Page” tutorial video and it was fantastic! Everything seems to work properly that was covered in the video.

Now, I have created a separate view controller that the user is brought to if they are signing up (NewUserHomeView Controller). This is a different view controller the user is brought to if they are just signing in (HomeViewController).

On the NewUserHomeViewController (and other view controllers later on) I want to be able to simply access and print out all of the data fields for that user. For now, this is just firstName, lastName, email, and password. Again, this project is essentially what Chris built in his Firebase iOS Login Page tutorial.

Currently, I have a segue that sends the string: (firstNameTextField.text! + " " + lastNameTextField.text!) to the NewUserHomeViewController. This should equal to the document ID for that user (I used .setData() to specify the document ID when a user is created). I am trying to use the string as the reference ID so that I can print out the data for that user. Hopefully that makes sense. Here is the code of the two view controllers:


import UIKit
import FirebaseAuth
import Firebase
import FirebaseFirestore

class SignUpViewController: UIViewController {

 **@IBOutlet** **weak** **var** firstNameTextField: UITextField!
 **@IBOutlet** **weak** **var** lastNameTextField: UITextField!
 **@IBOutlet** **weak** **var** emailTextField: UITextField!=
 **@IBOutlet** **weak** **var** passwordTextField: UITextField!
 **@IBOutlet** **weak** **var** signUpButton: UIButton!
 **@IBOutlet** **weak** **var** backButton: UIButton!
 **@IBOutlet** **weak** **var** errorLabel: UILabel!

override func viewDidLoad() {

    view.backgroundColor = .systemTeal

    // Do any additional setup after loading the view.


func setUpElements() {

    //hides error label
    errorLabel.alpha = 0
    //Style the elements


func validateFields() -> String? {

    // Check that all fields are filled in
    if firstNameTextField.text?.trimmingCharacters(in: .whitespacesAndNewlines) == "" || lastNameTextField.text?.trimmingCharacters(in: .whitespacesAndNewlines) == "" || emailTextField.text?.trimmingCharacters(in: .whitespacesAndNewlines) == "" || passwordTextField.text?.trimmingCharacters(in: .whitespacesAndNewlines) == "" {
        return "Please fill in all fields."
    //Check if this password is secure.
    let cleanedPassword = passwordTextField.text!.trimmingCharacters(in:


    if Utilities.isPasswordValid(cleanedPassword) == false {
        return "Please make sure your password is at least 8 characters, contains a special character and a number."
    return nil

@IBAction func signUpTapped(_ sender: Any) {

    self.performSegue(withIdentifier: "sourceVCtoDestinationVC", sender: self)
    //Validate the fields
    let error = validateFields()
    if error != nil {
    else {
        // Create cleaned versions of the data
        let firstName = firstNameTextField.text!.trimmingCharacters(in: .whitespacesAndNewlines)
        let lastName = lastNameTextField.text!.trimmingCharacters(in: .whitespacesAndNewlines)
        let email = emailTextField.text!.trimmingCharacters(in: .whitespacesAndNewlines)
        let password = passwordTextField.text!.trimmingCharacters(in: .whitespacesAndNewlines)
        //Create the user
        Auth.auth().createUser(withEmail: email, password: password) { (result, err) in
            // Check for errors
            if err != nil {
                // There was an error creating the usr
                self.showError("Error creating user")
            else {
                // User was created successfully, now store the firstname and lastname
                let db = Firestore.firestore()
                db.collection("users").document("\(firstName) \(lastName)").setData(["firstName":firstName, "lastName":lastName, "uid": result!.user.uid]) { (error) in
                    //check to see if saving is successful
                    if error != nil {
                        //Show error message
                        self.showError("Error saving user data")
                 //Transition to the home screen

func showError(_ message:String) {

    errorLabel.text = message
    errorLabel.alpha = 1

func transitionToHome() {

    let newUserHomeViewController1 = self.storyboard?.instantiateViewController(identifier: Constants.Storyboard.newUserHomeViewController) as? NewUserHomeViewController
    view.window?.rootViewController = newUserHomeViewController1

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if(segue.identifier == "sourceVCtoDestinationVC") {
        let destinationVC = segue.destination as! NewUserHomeViewController = firstNameTextField.text! + " " + lastNameTextField.text!
        // = firstName + lastName



import UIKit
import Firebase
import FirebaseFirestore
import FirebaseFirestoreSwift

class NewUserHomeViewController: UIViewController {

 **let** db = Firestore.firestore()

 **var** name: String?

 **@IBOutlet** **weak** **var** welcomeLabel: UILabel!

override func viewDidLoad() {

    let db = Firestore.firestore()

    welcomeLabel.text = name

    **let** docRef = db.collection("users").document(name!)

    docRef.getDocument { (document, error) in
                if let document = document, document.exists {
                    let dataDescription = ?? "nil"
                    print("Document data: \(dataDescription)")
        } else {
                    print("Document does not exist")


My code keeps outputting “Document does not exist” when ran. Sorry for the lengthy post, but I would really appreciate any help! I must be using the wrong syntax or something…

Thanks in advance,

I am happy to provide more of my code or any other information if needed!