UIScrollView Extensions (scroll to subview and get relative offset of subview)

UIScrollViewExtensions.swift

extension UIScrollView {
    func scrollSubViewToTop(_ subview: UIView, offset: CGFloat, animated: Bool) {
        let point = convert(subview.frame.origin, from: subview.superview ?? subview)
        setContentOffset(CGPoint(x: 0, y: point.y - offset), animated: animated)
    }
    
    func viewPortOffset(of subview: UIView) -> CGFloat {
        let point = convert(subview.frame.origin, from: subview.superview ?? subview)
        return point.y - contentOffset.y
    }
}