Filter ViewControllers in a NavigationController by a Protocol

UINavigationController+Extension.swift

// Important Protocol is marked @objc and conform to AnyObject
@objc protocol Hostable: AnyObject { }

extension UINavigationController {
    
    func viewControllers(conforming: Protocol) -> [UIViewController]? {
        return viewControllers.filter { $0.conforms(to: conforming) }
    }
    
    func popToFirstViewController(conforming: Protocol, animated: Bool) {
        if let destination = viewControllers(conforming: conforming)?.first {
            popToViewController(destination, animated: animated)
        }
    }
}