Swift Extension for adding borders to any side of UIView

UIView+Borders.swift

extension UIView {
    struct Side: OptionSet {
        let rawValue: Int

        static let left = Side(rawValue: 1 << 0)
        static let right = Side(rawValue: 1 << 1)
        static let top = Side(rawValue: 1 << 2)
        static let bottom = Side(rawValue: 1 << 3)
    }

    func addBorders(color: UIColor, width: CGFloat, to side: Side, for size: CGSize) {
        if side.contains(.left) {
            addBorder(color: color, frame: .init(x: 0, y: 0, width: width, height: size.height))
        }
        if side.contains(.right) {
            addBorder(color: color, frame: .init(x: size.width - width, y: 0, width: width, height: size.height))
        }
        if side.contains(.top) {
            addBorder(color: color, frame: .init(x: 0, y: 0, width: size.width, height: width))
        }
        if side.contains(.bottom) {
            addBorder(color: color, frame: .init(x: 0, y: size.height - width, width: size.width, height: width))
        }
    }

    private func addBorder(color: UIColor, frame: CGRect) {
        let border = CALayer()
        border.frame = frame
        border.backgroundColor = color.cgColor
        layer.addSublayer(border)
    }

    func removeBorders() {
        layer.sublayers?.forEach {
            guard $0 is BorderLayer else { return }
            $0.removeFromSuperlayer()
        }
    }
}

private class BorderLayer: CALayer {}

Usage

if isBorderEnabled {
    addBorders(color: .red, width: 1, to: [.top, .bottom], for: bounds.size)
} else {
    removeBorders()
}