Adding scale and fade animation to the layer

ViewController-Pulse-Animation-AddingAnimationsToTheLayers.swift

    func animatePulsatingLayerAt(index:Int) {
        
        //Giving color to the layer
        pulseArray[index].strokeColor = UIColor.darkGray.cgColor
        
        //Creating scale animation for the layer, from and to value should be in range of 0.0 to 1.0
        // 0.0 = minimum
        //1.0 = maximum
        let scaleAnimation = CABasicAnimation(keyPath: "transform.scale")
        scaleAnimation.fromValue = 0.0
        scaleAnimation.toValue = 0.9
        
        //Creating opacity animation for the layer, from and to value should be in range of 0.0 to 1.0
        // 0.0 = minimum
        //1.0 = maximum
        let opacityAnimation = CABasicAnimation(keyPath: #keyPath(CALayer.opacity))
        opacityAnimation.fromValue = 0.9
        opacityAnimation.toValue = 0.0
       
       //Grouping both animations and giving animation duration, animation repat count
        let groupAnimation = CAAnimationGroup()
        groupAnimation.animations = [scaleAnimation, opacityAnimation]
        groupAnimation.duration = 2.3
        groupAnimation.repeatCount = .greatestFiniteMagnitude
        groupAnimation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseOut)
        //adding groupanimation to the layer
        pulseArray[index].add(groupAnimation, forKey: "groupanimation")
        
    }