A UIView Extensions to help you constrains a view programatically and simplified

AutoLayout+Extension.swift

import UIKit
public extension UIView{
	
	func setWith(_ width: CGFloat){
		self.widthAnchor.constraint(equalToConstant: width).isActive = true
	}
	
	func setHeight(_ width: CGFloat){
		self.heightAnchor.constraint(equalToConstant: width).isActive = true
	}
	
	func centerVerticalToView(_ view : UIView){
		self.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
	}
	func centerHorizontalToView(_ view : UIView){
		self.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
	}
	
	
	func setTopAnchor(onview : UIView,topAnchor : CGFloat)  {
		self.topAnchor.constraint(equalTo: onview.topAnchor,constant: topAnchor).isActive = true
	}
	
	func pintoLeft(superview: UIView,space: CGFloat = 0.0){
		self.leadingAnchor.constraint(equalTo: superview.leadingAnchor,constant: space).isActive = true
	}
	
	func pintoLeft(superview: NSLayoutAnchor<NSLayoutXAxisAnchor>,space: CGFloat = 0.0){
		self.leadingAnchor.constraint(equalTo: superview,constant: space).isActive = true
	}
	
	func pintoRight(superview: UIView,space: CGFloat = 0.0){
		self.trailingAnchor.constraint(equalTo: superview.trailingAnchor,constant: space).isActive = true
	}
	
	func pintoRight(superview: NSLayoutAnchor<NSLayoutXAxisAnchor>,space: CGFloat = 0.0){
		self.leadingAnchor.constraint(equalTo: superview,constant: space).isActive = true
	}
	func pintoTop(superview: UIView,space: CGFloat = 0.0){
		self.topAnchor.constraint(equalTo: superview.topAnchor,constant: space).isActive = true
	}
	//
	func pintoTop(superview: NSLayoutYAxisAnchor,space: CGFloat = 0.0){
		self.topAnchor.constraint(equalTo: superview,constant: space).isActive = true
	}
	
	func pintoBottom(superview: NSLayoutYAxisAnchor,space: CGFloat = 0.0){
		self.bottomAnchor.constraint(equalTo: superview,constant: space).isActive = true
	}
	
	
	func pintoBottom(superview: UIView,space: CGFloat = 0.0){
		self.bottomAnchor.constraint(equalTo: superview.bottomAnchor,constant: space).isActive = true
	}
	
	func constraintoTop(superview view : UIView,
				  topSpace : CGFloat = 0,
				  leadingSpace : CGFloat = 0,
				 trailingSpace : CGFloat = 0){
		self.topAnchor.constraint(equalTo: view.topAnchor,constant: topSpace).isActive = true
		self.leadingAnchor.constraint(equalTo: view.leadingAnchor,constant: leadingSpace).isActive = true
		self.trailingAnchor.constraint(equalTo: view.trailingAnchor,constant: trailingSpace).isActive = true
	}
	
	
	func constrainToSuperViewNoGuide(on view : UIView){
		//let guide = view.safeAreaLayoutGuide
		self.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
		self.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true
		self.bottomAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
		self.topAnchor.constraint(equalTo: view.topAnchor).isActive = true
		
	}
	func constrainToBelowView(below view : UIView){
		let guide = view.safeAreaLayoutGuide
		self.leadingAnchor.constraint(equalTo: guide.leadingAnchor).isActive = true
		self.trailingAnchor.constraint(equalTo: guide.trailingAnchor).isActive = true
		self.bottomAnchor.constraint(equalTo: guide.bottomAnchor).isActive = true
		self.topAnchor.constraint(equalTo: view.bottomAnchor).isActive = true
		
	}
	
	func constrainToSuperView(on view : UIView,
				 top: CGFloat = 0,
				leading:CGFloat = 0,
				trailing:CGFloat = 0,
				bottom: CGFloat = 0){
		
		let guide = view.safeAreaLayoutGuide
		self.leadingAnchor.constraint(equalTo: guide.leadingAnchor,constant: leading).isActive = true
		self.trailingAnchor.constraint(equalTo: guide.trailingAnchor,constant: trailing).isActive = true
		self.bottomAnchor.constraint(equalTo: guide.bottomAnchor,constant: bottom).isActive = true
		self.topAnchor.constraint(equalTo: guide.topAnchor,constant: top).isActive = true
		
	}
	
	func constrainTopOfSuperView(on view : UIView,
															 leadingConstant:CGFloat = 0,
															 trailingConstant : CGFloat = 0){
		let guide = view.safeAreaLayoutGuide
		self.leadingAnchor.constraint(equalTo: guide.leadingAnchor,constant: leadingConstant).isActive = true
		self.trailingAnchor.constraint(equalTo: guide.trailingAnchor,constant: trailingConstant).isActive = true
		self.topAnchor.constraint(equalTo: guide.topAnchor).isActive = true
		
	}
	
	func constrainBelowSuperViewsTopView(superview : UIView,
																			 below topview : UIView,
																			 spacing: CGFloat = 0){
		
		let guide = superview.safeAreaLayoutGuide
		self.leadingAnchor.constraint(equalTo: guide.leadingAnchor).isActive = true
		self.trailingAnchor.constraint(equalTo: guide.trailingAnchor).isActive = true
		self.bottomAnchor.constraint(equalTo: guide.bottomAnchor).isActive = true
		self.topAnchor.constraint(equalTo: topview.bottomAnchor,constant: spacing).isActive = true
		
	}
	
	
	
	func constrainBelowView(below: UIView,
				topSpace:CGFloat = 0,
				bottomSpace:CGFloat = 0,
				eadingSpace:CGFloat = 0,
				tralingSpace:CGFloat = 0 ,
				withBottomAchor:Bool = false){
		
		
		self.topAnchor.constraint(equalTo: below.bottomAnchor,constant: topSpace).isActive = true
		self.leadingAnchor.constraint(equalTo: self.leadingAnchor,constant: leadingSpace).isActive = true
		self.trailingAnchor.constraint(equalTo: self.trailingAnchor,constant: tralingSpace).isActive = true
		if withBottomAchor {
			self.bottomAnchor.constraint(equalTo: self.bottomAnchor,constant: bottomSpace).isActive = true
		}
		
	}
	
	
	func addShadow(){
		self.layer.cornerRadius = 10
		self.layer.shadowColor = UIColor.lightGray.cgColor
		self.layer.shadowOffset = CGSize(width: 0.0, height: 0.0)
		self.layer.shadowRadius = 3
		self.layer.shadowOpacity = 0.9
		self.layer.masksToBounds = false
		
	}
}

//Usage
lazy var mapView: MKMapView = {
		let map = MKMapView()
		map.translatesAutoresizingMaskIntoConstraints = false
		map.mapType = MKMapType.standard
		return map
	}()

lazy var navBack: UIView = {
		let button = UIView()
		button.translatesAutoresizingMaskIntoConstraints = false
		return button
	}()

override func viewWillLayoutSubviews() {
		  view.addSubview(mapView)
		  mapView.constrainToSuperView(on: view)
		  mapView.addSubview(navBack)
		  navBack.pintoTop(superview: mapView.safeAreaLayoutGuide.topAnchor,space: 20)
		  navBack.pintoLeft(superview: mapView,space: 20)
 }

Nice! Thank you!