Swift 4 Extension for adding border to one side of UIView

UIView+Border.swift

// Ready for Swift 4

extension UIView {
    
    // Example usage: myView.addBorder(toSide: .left, withColor: .red, andThickness: 1.0)
    
enum Side {
    case left, right, top, bottom
  }

  func addBorder(toSide side: Side, withColor color: UIColor, andThickness thickness: CGFloat) {

    let border = CALayer()
    border.backgroundColor = color.cgColor

    switch side {
    case .left: border.frame = CGRect(x: bounds.minX, y: bounds.minY, width: thickness, height: bounds.height); break
    case .right: border.frame = CGRect(x: bounds.maxX, y: bounds.minY, width: thickness, height: bounds.height); break
    case .top: border.frame = CGRect(x: bounds.minX, y: bounds.minY, width: bounds.width, height: thickness); break
    case .bottom: border.frame = CGRect(x: bounds.minX, y: bounds.maxY, width: bounds.width, height: thickness); break
    }
    print(border.frame)
    layer.addSublayer(border)
  }
}