Add & Remove borders on a UIView for various positions.

UIView+Border.swift

//
//  UIView+Border.swift
//
//  Created by Manjunath Chandrashekar on 03/11/18.
//  Copyright © 2018 Manjunath Chandrashekar. All rights reserved.
//

import Foundation

extension UIView {
    
    enum BorderPosition: String {
        case top    = "topBorder"
        case right  = "rightBorder"
        case bottom = "bottomBorder"
        case left   = "leftBorder"
    }
    
    func addBorder(position: BorderPosition, color: UIColor = .gray, width: CGFloat = 2.0) {
        
        for layer in self.layer.sublayers ?? [] {
            // If layer already exists, remove it before adding again.
            if position.rawValue == layer.name {
                layer.removeFromSuperlayer()
            }
        }
        
        let border = CALayer()
        border.name = position.rawValue
        border.backgroundColor = color.cgColor
        switch position {
        case .top:
            border.frame = CGRect(x: 0, y: 0, width: self.frame.size.width, height: width)
        case .right:
            border.frame = CGRect(x: self.frame.size.width - width, y: 0, width: width, height: self.frame.size.height)
        case .bottom:
            border.frame = CGRect(x: 0, y: self.frame.size.height - width, width: self.frame.size.width, height: width)
        case .left:
            border.frame = CGRect(x: 0, y: 0, width: width, height: self.frame.size.height)
        }
        self.layer.addSublayer(border)
    }
    
    func removeBorder(position: BorderPosition) {
        for layer in self.layer.sublayers ?? [] {
            if position.rawValue == layer.name {
                layer.removeFromSuperlayer()
            }
        }
    }
}