Gtk.Dialog.prototype.add_button

function add_button(button_text:String, response_id:Number):Gtk.Widget {
    // Gjs wrapper for gtk_dialog_add_button()
}

Adds a button with the given text (or a stock button, if button_text is a stock ID) and sets things up so that clicking the button will emit the Gtk.response signal with the given response_id. The button is appended to the end of the dialog's action area. The button widget is returned, but usually you don't need it.