GObjectIntrospection/SimpleObserver

Super low-budget TpSimpleObserver example in GJS. 

const Tp = imports.gi.TelepathyGLib;
const Mainloop = imports.mainloop;

function observe_channels(observer, account, connection, channels,
                          dispatch_op, requests, context, user_data)
{
    print("observe_channels");

    print("account = " + account.get_object_path());
    print("connection = " + connection.get_object_path());

    for (let i in channels) {
        let channel = channels[i];

        print("channel = " + channel.get_object_path());
    }

    if (dispatch_op != null)
      print("dispatch_op = " + dispatch_op.get_object_path());
    else
      print("dispatch_op = (null)");

    for (let i in requests) {
      let request = requests[i];

      print("request = " + request.get_object_path());
    }

    context.accept();
}

let dbus = Tp.DBusDaemon.dup();
let observer = Tp.SimpleObserver.new(dbus, true, "JSObserver", true,
                                     observe_channels);

observer.add_observer_filter({
  "org.freedesktop.Telepathy.Channel.ChannelType": Tp.IFACE_CHANNEL_TYPE_TEXT,
});

try {
    observer.register();
    Mainloop.run("");
} catch (e) {
    print("ERROR: " + e);
}