Make autolayout easier with this extension.

AutoLayoutExtension.swift

extension UIView {
    
    func fillContainer() {
        anchor(top: superview?.topAnchor, leading: superview?.leadingAnchor,
               bottom: superview?.bottomAnchor, trailing: superview?.trailingAnchor)
    }
    
    // When you use this function don't pass "size" parameter into "anchor" function
    func anchorSize(to view: UIView) {
        widthAnchor.constraint(equalTo: view.widthAnchor).isActive = true
        heightAnchor.constraint(equalTo: view.heightAnchor).isActive = true
    }
    
    func anchor(top: NSLayoutYAxisAnchor? = nil, leading: NSLayoutXAxisAnchor? = nil,
                bottom: NSLayoutYAxisAnchor? = nil, trailing: NSLayoutXAxisAnchor? = nil,
                                    padding: UIEdgeInsets = .zero, size: CGSize = .zero ) {
        
        translatesAutoresizingMaskIntoConstraints = false
        
        if let top = top {
            topAnchor.constraint(equalTo: top, constant: padding.top).isActive = true
        }
        
        if let leading = leading {
            leadingAnchor.constraint(equalTo: leading, constant: padding.left).isActive = true
        }
        
        if let bottom = bottom {
            bottomAnchor.constraint(equalTo: bottom, constant: -padding.bottom).isActive = true
        }
        
        if let trailing = trailing {
            trailingAnchor.constraint(equalTo: trailing, constant: -padding.right).isActive = true
        }
        
        if size.width != 0 {
            widthAnchor.constraint(equalToConstant: size.width).isActive = true
        }
        
        if size.height != 0 {
            heightAnchor.constraint(equalToConstant: size.height).isActive = true
        }
    }
}