bus.off() without parameters can be dangerous

[axelpale]

Today the following caveat happened to me:

bus.on('join', function () { do A });
...
var route;
(function tick() {
  bus.off(route);
  route = bus.on('quit', function () { do B and call tick });
  setTimeout(tick, 1000);
}());

There off call seems to take a parameter but because all off parameters are undefined, it acts like empty off call. This is a caveat of JavaScript in general but could there be a way to prevent this kind of thing happening for example by empasizing that route variables should be initialized with an empty string?