How to update data in the firebase using swift?

Question

I have made an sign up and also login and it works! but now I want to edit the data in the Firebase. Can anyone help me how to do it? Thanks you

Here the Sign Up View Controller

import UIKit    
import FirebaseAuth    
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 ErrorLabel: UILabel!
    override func viewDidLoad() {
        super.viewDidLoad()

        // Do any additional setup after loading the view.

        setUpElements()
    }
    func setUpElements(){
        ErrorLabel.alpha = 0
    }

    func validateFields()->String? {

        //check that all the fields are fill

        if FirstNameTextfield.text?.trimmingCharacters(in: .whitespacesAndNewlines) == "" || LastNameTextfield.text?.trimmingCharacters(in: .whitespacesAndNewlines) == "" || EmailTextField.text?.trimmingCharacters(in: .whitespacesAndNewlines) == "" || PasswordTextfield.text?.trimmingCharacters(in: .whitespacesAndNewlines) == ""
            {
            return "Please fill up all the Fields"
        }

        //check the password if the password is secure
        let cleanedPassword = PasswordTextfield.text!.trimmingCharacters(in: .whitespacesAndNewlines)

        if Utilities.isPasswordValid(cleanedPassword) == false{
            return "Please enter at least 8 characters, with a number and characteristic symbol"
        }

        return nil
    }


    @IBAction func SignUpTap(_ sender: Any) {

        let error = validateFields()

        if error != nil{
            showError(message: error!)
        }
        else {
            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)


            Auth.auth().createUser(withEmail: Email, password: Password) { (result, err) in

                if err != nil{
                    self.showError(message: "Error creating the user")
                }
                else {

                let db = Firestore.firestore()


                    db.collection("users").addDocument(data:["FirstName":FirstName, "LastName":LastName, "uid": result!.user.uid]) { (Error) in

                        if error != nil{
                            self.showError(message: "Cannot saving user data" )
                        }
                    }

                    self.transitionToHomePage()

                }
            }
        }            
    }

    func showError( message:String){
        ErrorLabel.text = message
        ErrorLabel.alpha = 1
    }

    func transitionToHomePage(){
         let TabHomeViewController = storyboard?.instantiateViewController(identifier: Constrants.Storyboard.TabHomeViewController) as? TabHomeViewController

        view.window?.rootViewController = TabHomeViewController
        view.window?.makeKeyAndVisible()
    }
}

Here my login VC

@IBAction func LoginTap(_ sender: Any) {

        let Email = EmailTextField.text!.trimmingCharacters(in: .whitespacesAndNewlines)
        let Password = PasswordTextfield.text!.trimmingCharacters(in: .whitespacesAndNewlines)
        Auth.auth().signIn(withEmail: Email, password: Password) { (result, error) in

            if error != nil{
                self.ErrorLabel.text = error!.localizedDescription
                self.ErrorLabel.alpha = 1
            }
            else{
                let TabHomeViewController = self.storyboard?.instantiateViewController(identifier: Constrants.Storyboard.TabHomeViewController) as? UITabBarController

                self.view.window?.rootViewController = TabHomeViewController
                self.view.window?.makeKeyAndVisible()
            }

And here my Account View Controller

import UIKit

import FirebaseAuth

import FirebaseFirestore

import Firebase

class AccountViewController: UIViewController {

    @IBOutlet weak var FNameTextField: UITextField!


    @IBOutlet weak var LNameTextField: UITextField!


    @IBOutlet weak var EmailTextField: UITextField!


    @IBOutlet weak var PasswordTextField: UITextField!

    override func viewDidLoad() {
        super.viewDidLoad()

    }


    @IBAction func logoutbutton(_ sender: Any) {
        do{
            try Auth.auth().signOut()
            performSegue(withIdentifier: "signout", sender: nil)
        }
        catch{
            print(error)
        }
    } 
}

Answer 1

You can use this function:

func updateFirestoreUserProfile(uid: String, data: [String:Any]) {
    Firestore.firestore().collection("users").document(uid).updateData(data) { err in
        if let err = err {
            print("Error updating document: \(err) ")
        }
        else {
            print("Document successfully updated")
        }
    }
}

You can use the function like this:

let data = [
        "FirstName": name,
        "LastName": surname
    ]

updateFirestoreUserProfile(uid: user.uid, data: data)