TheBinder5.swift

extension ProfileViewController {

    static func makeViewController(_ userService: UserService) -> ProfileViewController {

        let viewController = ProfileViewController()

        ...
      
        viewController.friendsView.reactive.selectedItem
            .with(latestFrom: userService.friends, combine: itemAtIndex)  // Take element at selected index from friends array
            .bind(to: viewController) { viewController, friend in
                let userService = userService.makeUserService(for: friend)
                viewController.presentFriendViewController(userService)
            }
      
        ...
    }

    private func presentFriendViewController(_ userService: UserService) {
        let viewController = ProfileViewController.makeViewController(userService)
        present(viewController, animated: true)
    }
}