Designable view from xib, without optimisation

UIViewXib.swift

@IBDesignable
class UIViewXib: UIView {
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        loadViewFromNib()
    }
    
    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        loadViewFromNib()
    }
    
    private func loadViewFromNib() {
        let bundle = Bundle(for: type(of: self))
        let nib = UINib(nibName: String(describing: type(of: self)), bundle: bundle)
        if let view = nib.instantiate(withOwner: self, options: nil).first as? UIView {
            addSubview(view)
            view.frame = bounds
            view.autoresizingMask = [.flexibleWidth, .flexibleHeight]
        }
        // low priority default height constraint
        let heightConst = heightAnchor.constraint(equalToConstant: 100)
        heightConst.priority = .init(1)
        heightConst.isActive = true
    }
}