An extension to add useful pinning tools to UIView.

UIView+pin.swift

//
//  UIView+pin.swift
//
//  Created by Jamie Bishop on 2018-07-20.
//  Copyright © 2018 Jamie Bishop.
//  
//  Feel free to use this code without credit.
//  https://gist.github.com/jamiebishop

import UIKit

extension UIView {
    /// Pins this view to it's superview.
    func pinToSuperview() {
        guard let superview = superview else { fatalError("UIView+pinToSuperview: \(description) has no superview.") }
        pin(to: superview)
    }
    
    /// Pins this view to another view.
    func pin(to view: UIView) {
        leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
        rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
        topAnchor.constraint(equalTo: view.topAnchor).isActive = true
        bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
    }
}