How to be certain that the callback returns an error

[HighSoftWare96]

I was wondering if there is a correct way to know if there was an error retrieving the network data requested in the callback, I think this is not a good way to do that:

NetworkInfo.getSSID(ssid => {
  if (ssid == "error") {
     // error
   } else {
    // OK
   }
});