Simple Example of Clean Method Implementation.

ViewController+UITableViewDelegate.swift

import UIKit

extension ViewController: UITableViewDelegate {
    
    // Some UITableViewDelegate method
    // ...
  
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        let verticalOffset = tableView.contentOffset.y
        verticalOffset >= 64
            ? setupNavbarAppereanceNotTransparentWhenScolling()
            : setupNavBarAppereanceTransparentWhenScrolling()
    }
    
}

extension ViewController {
    
    private func setupNavbarAppereanceNotTransparentWhenScolling() {
        navigationController?.unTransparentNavBar(tintColor: Resources.Color.primaryColor, barTintColor: .white)
        let textAttributes = [NSAttributedStringKey.foregroundColor: UIColor.black]
        navigationController?.navigationBar.titleTextAttributes = textAttributes
    }
    
    private func setupNavBarAppereanceTransparentWhenScrolling() {
        navigationController?.transparentNavBar(tintColor: .white)
        let textAttributes = [NSAttributedStringKey.foregroundColor: UIColor.clear]
        navigationController?.navigationBar.titleTextAttributes = textAttributes
    }
}