A wrapper that allows you to set animation and completion handler in a more consistent way

UIKit_Animator_API.swift

extension UIKit.UIView {

	public class Animator {
		fileprivate var animatorBlock: ((@escaping () -> (), @escaping (Bool) -> ()) -> ())
		fileprivate var animations: () -> () = { _ in }
		
		public init(animatorBlock: @escaping ((@escaping () -> (), @escaping (Bool) -> ()) -> ())) {
			self.animatorBlock = animatorBlock
		}
		
		public func animations(_ animations: @escaping () -> ()) -> Self {
			self.animations = animations
			return self
		}
		
		public func completion(_ completion: @escaping (Bool) -> ()) {
			animatorBlock(animations, completion)
		}
	}

	public static func animate(withDuration duration: TimeInterval) -> Animator {
		return Animator(animatorBlock: {
			UIView.animate(withDuration: duration, animations: $0, completion: $1)
		})
	}
	
	public static func animate(withDuration duration: TimeInterval, delay: TimeInterval, options: UIViewAnimationOptions) -> Animator {
		return Animator(animatorBlock: {
			UIView.animate(withDuration: duration, delay: delay, options: options, animations: $0, completion: $1)
		})
	}
	
	public static func animate(withDuration duration: TimeInterval, delay: TimeInterval, usingSpringWithDamping: CGFloat, initialSpringVelocity: CGFloat, options: UIViewAnimationOptions ) -> Animator {
		return Animator(animatorBlock: {
			UIView.animate(withDuration: duration, delay: delay, usingSpringWithDamping: usingSpringWithDamping, initialSpringVelocity: initialSpringVelocity, options: options, animations: $0, completion: $1)
		})
	}
	
	public static func animateKeyframes(withDuration duration: TimeInterval, delay: TimeInterval, options: UIViewKeyframeAnimationOptions) -> Animator {
		return Animator(animatorBlock: {
			UIView.animateKeyframes(withDuration: duration, delay: delay, options: options, animations: $0, completion: $1)
		})
	}
	
}


// Example usage

// Vanilla animation
UIView.animate(withDuration: 5)
			.animations {
				self.view.backgroundColor = .red
			}
			.completion { _ in }

// Animation with delay
UIView.animate(withDuration: 5, delay: 1, options: UIViewAnimationOptions.curveEaseInOut)
			.animations {
				self.view.backgroundColor = .green
			}.completion { _ in }

// Animation with spring velocity
let v = UIView(frame: CGRect(x: 0, y: 0, width: 100, height: 100))
v.backgroundColor = .purple
self.view.addSubview(v)
UIView.animate(withDuration: 5, delay: 1, usingSpringWithDamping: 0.1, initialSpringVelocity: 40, options: UIViewAnimationOptions.curveEaseInOut)
			.animations {
				v.frame.origin.x = 150
			}.completion({ _ in
				v.frame.origin.x = 0
			})


// Animation with key frames.
UIView.animateKeyframes(withDuration: 5
			, delay: 0
			, options: UIViewKeyframeAnimationOptions.calculationModeLinear)
			.animations {
				UIView.addKeyframe(withRelativeStartTime: 0.0, relativeDuration: 0.2) {
					v.frame.origin = CGPoint(x: 20, y: 0)
				}
				UIView.addKeyframe(withRelativeStartTime: 0.2, relativeDuration: 0.2) {
					v.frame.origin = CGPoint(x: 20, y: 20)
				}
			}
			.completion {_ in}