touchBarDelegate.swift

extension WindowController: NSTouchBarDelegate {
    func touchBar(_ touchBar: NSTouchBar, makeItemForIdentifier identifier: NSTouchBarItemIdentifier) -> NSTouchBarItem? {
        switch identifier {
        case NSTouchBarItemIdentifier.label:
            // Create custom touch bar Item
            let custom = NSCustomTouchBarItem(identifier: identifier)
            custom.customizationLabel = "Label Title"
            
            // Create label as NSTextField
            let label = NSTextField(labelWithString: "Hello, TouchBar")
            label.textColor = NSColor.green
            
            // Assign custom item's view
            custom.view = label
            
            return custom
        default:
            return nil
        }
    }
}