Provides information on the result of a command.

A trivial implementation would be as follows :

streamLink.publishToSubject("/SUBJECT", fieldData, {
        onCommandError : function(subject, commandErrorEvent)
        {
                console.log("Publish Error : " + commandErrorEvent.getError());
        },
        onCommandOk : function(subject)
        {
                console.log("Publish to " + subject + " Succesful");
        }
}, null);