Google Sign In - View Controller - Configure GIDSignIn singleton

GoogleSignInViewController_Singleton.swift

import GoogleSignIn

class ViewController: UIViewController {
    // ...
  
    override func viewDidLoad() {
        super.viewDidLoad()
        
        /***** Configure Google Sign In *****/ 
      
        GIDSignIn.sharedInstance()?.delegate = self
        
        // GIDSignIn.sharedInstance()?.signIn() will throw an exception if not set.
        GIDSignIn.sharedInstance()?.uiDelegate = self
      
        // Attempt to renew a previously authenticated session without forcing the
        // user to go through the OAuth authentication flow.
        // Will notify GIDSignInDelegate of results via sign(_:didSignInFor:withError:)
        GIDSignIn.sharedInstance()?.signInSilently()
      
        // ...
    }
}