UI 요소의 오토레이아웃을 잡을때 UIView 클래스를 확장하여 더 편한 방식으로 코드를 작성할 수 있다.

import UIKit

extension UIView{
    func anchor(top: NSLayoutYAxisAnchor?, left: NSLayoutXAxisAnchor?, right: NSLayoutXAxisAnchor?, bottom: NSLayoutYAxisAnchor?, paddingTop: CGFloat, paddingLeft: CGFloat, paddingRight: CGFloat, paddingBottom:CGFloat, width: CGFloat, height: CGFloat){

        translatesAutoresizingMaskIntoConstraints = false

        if let top = top {
            self.topAnchor.constraint(equalTo: top, constant: paddingTop).isActive = true
        }

        if let left = left {
            self.leftAnchor.constraint(equalTo: left, constant: paddingLeft).isActive = true
        }

        if let right = right {
            self.rightAnchor.constraint(equalTo: right, constant: -paddingRight).isActive = true
        }

        if let bottom = bottom {
            self.bottomAnchor.constraint(equalTo: bottom, constant: -paddingBottom).isActive = true
        }

        if width != 0{
            self.widthAnchor.constraint(equalToConstant: width).isActive = true
        }

        if height != 0{
            self.heightAnchor.constraint(equalToConstant: height).isActive = true
        }
    }
}

Reference

1. Writing an extension for setting up auto layout constraints in Swift (opens new window)