Using NSNotificationCenter in Swift

I'm working on a full post for later this week, but as I sat down to write some code this afternoon, I needed to implement an NSNotification observer on a text field (namely, UITextFieldTextDidChangeNotification) and stopped for a moment to think about whether I should implement it the same way I would have in Objective-C, or if their was a more Swift way of doing things.

My initial thought was to use my go-to method for notifications, addObserver:selector:name:object: but that looked like this:

let notificationCenter = NSNotificationCenter.defaultCenter()
notificationCenter.addObserver(
    self,
    selector: "textFieldTextChanged:",
    name:UITextFieldTextDidChangeNotification,
    object: nil
)

func textFieldTextChanged(sender : AnyObject) {
    sendButton.enabled = messageField.text.utf16count > 0
}

and the thought of typing out a selector name in an un-checked string scares the U+1F4A9/U+E05A out of me, so I decided on the method I'm less familiar with, but the block based approach of addObserverForName:object:queue:usingBlock: seemed much more in-line with where I want to be thinking as a Swift developer.

let notificationCenter = NSNotificationCenter.defaultCenter()
let mainQueue = NSOperationQueue.mainQueue()

var observer = notificationCenter.addObserverForName(UITextFieldTextDidChangeNotification, object: nil, queue: mainQueue) { _ in
        self.sendButton.enabled = self.messageField.text.utf16count > 0
}

Now I'm no longer dependent on spelling the selector correctly, and I'm writing trailing closures rather than transposing the Objective-C way of doing things to a new Swift context.  

Prefer one over the other? Leave a comment and keep the discussion going.