Disconnecting session with Autobahn JS

Question

I have problems to disconnect the session to the websocket in my angularJS app. I know that Autobahn JS provides a diconnect() function, but it still not works.

Here is the connection part:

connect : function(){
    var deferred = $q.defer();
    session = new ab.Session('ws://the address', function(){ 
        console.log("Connection open");
        deferred.resolve(session);
    }, function(){
        console.log("Connection closed");
        //Shared.pushAlert("info", "Connection has been closed");
    });
    return deferred.promise;
}

Thank you for any suggestions