Swift 3: Realm creates additional object instead of updating the exisiting one

Question

In my AppDelegate

let realm = try! Realm()
    print("number of users")
    print(realm.objects(User.self).count)
    if !realm.objects(User.self).isEmpty{
        if realm.objects(User.self).first!.isLogged {
            User.current.setFromRealm(user: realm.objects(User.self).first!)
            let storyboard = UIStoryboard(name: "Main", bundle: nil)
            let viewController = storyboard.instantiateViewController(withIdentifier :"TabBar") as! CustomTabBarController
            self.window?.rootViewController = viewController
        }
    } else {
        try! realm.write { realm.add(User.current) }
    }

I create user only when there are no user objects across the app

thanks to this answer I update my object in the following way

public func update(_ block: (() -> Void)) {
    let realm = try! Realm()
    try! realm.write(block)
}

But it turns out it creates new User object. How to always update the already existing one instead of creating new object?

Note that I use User.current since my object is a singleton

After I login and logout, it prints number of users = 2, which means that updating already existing user creates a new one

Answer 1

Realm will check if the object exist or not for you. Only use add and update.

// Create or update the object
try? realm.write {
   realm.add(self, update: true)
}     

Documentation :

 - parameter object: The object to be added to this Realm.
 - parameter update: If `true`, the Realm will try to find an existing copy of the object (with the same primary
                     key), and update it. Otherwise, the object will be added.