UIView Extension to Add An Auto-Layout SubView With Equal All-Around Constraints (Fill)

UIViewExtension.swift

extension UIView {
    /* ################################################################## */
    /**
     This allows us to add a subview, and set it up with auto-layout constraints to fill the superview.
     
     - parameter inSubview: The subview we want to add.
     */
    func addContainedView(_ inSubView: UIView) {
        addSubview(inSubView)
        
        inSubView.translatesAutoresizingMaskIntoConstraints = false
        inSubView.topAnchor.constraint(equalTo: topAnchor, constant: 0).isActive = true
        inSubView.trailingAnchor.constraint(equalTo: trailingAnchor, constant: 0).isActive = true
        inSubView.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 0).isActive = true
        inSubView.bottomAnchor.constraint(equalTo: bottomAnchor, constant: 0).isActive = true
    }
}