GMenu and Applcation example

gmenu.js

#!/usr/bin/gjs

const Gio = imports.gi.Gio;
const Gtk = imports.gi.Gtk;
const Lang = imports.lang;


const App = new Lang.Class ({
    Name : "App",
    
    _init : function () {
        this.app = new Gtk.Application ({
            application_id: 'example.myapp',
            flags: Gio.ApplicationFlags.FLAGS_NONE
        });

        this.app.connect('activate', Lang.bind(this, this._on_activate));
        this.app.connect('startup', Lang.bind(this, this._on_startup));
    },
    
    _on_activate : function () {
        this._window.present ();
    },
    
    _on_startup : function () {
        this._build_ui ();
    },
    
    _build_ui: function () {
        this._window = new Gtk.ApplicationWindow  ({ application: this.app,
                                                   window_position: Gtk.WindowPosition.CENTER,
                                                   title: "Welcome to GNOME" });
        
        let menu = new Gio.Menu ();
        menu.append ("SuperMegaHiperDuper legal", "app.quit");
        
        this.app.set_app_menu (menu);
        
        let quitAction = new Gio.SimpleAction ({ name: 'quit' });
        quitAction.connect('activate', Lang.bind(this,
            function() {
                this._window.destroy();
            }));
         this.app.add_action(quitAction);

        this._window.set_default_size(600, 400);
        this._window.show_all();
    },
});

let app = new App ();
this.app.app.run (ARGV);