BLE Disconnect button help needed js

Yesterday I wrote myself a disconnect button for:

LED On!
LED Off!


from the tutorial page, I did however apparantly not save this small code snippet and I did not find it in my browser history.
I did try this:

  async function disconnect(){
    gatt.disconnect();
 } 

and
deviceObj.gatt.disconnect().
which both did not work.
Puck.js2.1a