not able to detect mongodb shutdown

My code:

  db = mongoose.connect(
    config[MONGO_HOST_CONF],
    config[MONGO_ACCOUNTS_DB_CONF],
    config[MONGO_PORT_CONF]
    }
  );

  db.connection.on('opening', function() {
    console.log("connecting");
  });

  db.connection.on('open', function() {
    console.log("connected");
  });

  db.connection.on('error', function() {
    console.log("disconnected");
  });
  db.connection.on('close', function() {
    console.log("disconnected");
  });

When I start my webserver which then opens a connection to mongodb, I can see "connected" in logs.

But when I do a mongodb stop, I dont see "disconnected" in logs. Neither do I see "connecting".

I am trying to detect if for some reason mongodb went down. Then reconnect before bailing out.

What is wrong above?