PulsatingButton.swift

final class PulsatingButton: UIButton {
   private var timer: Timer?

   func setup() {
       self.layer.shouldRasterize = true

       self.timer = Timer.scheduledTimer(timeInterval: 5.0, target: self, selector: #selector(timerAction), userInfo: nil, repeats: true)

   }
   private let buttonScaleIdentity = CGAffineTransform.init(scaleX: 1.75, y: 1.75)

   func timerAction(timer: Timer) {

       UIView.animate(withDuration: 0.5, delay: 0.3, options: .curveEaseInOut, animations: {
           self.transform = self.buttonScaleIdentity
       }) { (completed) in
           if (completed) {
               UIView.animate(withDuration: 0.5, delay: 0.3, options: .curveEaseInOut,
                              animations: {
                               self.transform = CGAffineTransform.identity
                   }, completion: { (_) in })
           }
       }
   }

   deinit {
       self.timer?.invalidate()
   }
}