Enable/disable UIButton according to number of characters in UITextField in ReactiveCocoa 4

Question

I want to set the enabled property of a UIButton to true iff there is at least one character in a UITextField. How can this be achieved in Reactive Cocoa 4?

Answer 1

You can do it like this:

NSNotificationCenter.defaultCenter()
  .rac_notifications(UITextFieldTextDidChangeNotification, object: textField)
   .map { $0.object as! UITextField }
   .map { $0.text }
   .map { $0.isEmpty }
   .startWithNext { button.enabled = !$0 }