UITabBarController extension for hiding and showing TabBar

UITabBarController+TabBarAnimations.swift

// Also works well on iPhone X
// Example usage:
/*  
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        tabBarController?.setTabBarVisible(visible: false, animated: true)
    }
*/

extension UITabBarController {
    
    // Inspired by https://gist.github.com/krodak/2bd8139c5f69b9434008
    func setTabBarVisible(visible:Bool, animated:Bool) {
        
        // bail if the current state matches the desired state
        let isVisible = tabBar.frame.origin.y < UIScreen.main.bounds.height
        guard (isVisible != visible) else { return }
        
        // get a frame calculation ready
        let frame = tabBar.frame
        let height = frame.size.height
        let offsetY = (visible ? -height : height)
        
        // zero duration means no animation
        let duration:TimeInterval = (animated ? 0.3 : 0.0)
        
        //  animate the tabBar
        UIView.animate(withDuration: duration) {
            self.tabBar.frame = frame.offsetBy(dx: 0, dy: offsetY)
        }
    }
    
}