Swift: Check if app running as Catalyst with 'Optimized for mac' setting enabled

UIDevice+CatalystOptimized.swift

// Credit: https://steipete.com/posts/forbidden-controls-in-catalyst-mac-idiom/

extension UIDevice {
    /// Checks if we run in Mac Catalyst Optimized For Mac Idiom
    var isCatalystMacIdiom: Bool {
        if #available(iOS 14, *) {
            return UIDevice.current.userInterfaceIdiom == .mac
        } else {
            return false
        }
    }
}

Alternative (if native macOS is also supported):

var isNativeMacAppOrCatalystOptimized: Bool {
#if os(iOS)
    return UIDevice.current.userInterfaceIdiom == .mac
#elseif os(macOS)
    return true
#endif
}