Allow to clear all subscribers for a topic by changing uid to a number

[pvdz]

I wanted to do PubSub.unsubscribe('topic') but can't. Instead to unsubscribe an event I either have to maintain the returned ids or I have to maintain a reference to the handler function.

If the unique id returned by subscribe were to just be var token = ++lastUid, you could overload the unsubscribe method by checking for a number to do the same as strings do right now. Then you could use the string case to drop all handlers for a certain topic.

The only impact I see right now is to users who rely on the subscribe return value being a string. I'm not sure why anyone would though since for them it's just a token.

The fixes are trivial but I don't know whether you're open to such a change.

[mroderick]

If I understand correctly, you would like a way to remove all subscriptions for a topic.

A dedicated method would probably be better than further overloading the unsubscribe method. Perhaps it could look like: PubSub.clearSubscriptions('topic')

How would that affect hierarchical topics?

var func = function NOOP(){};

PubSub.subscribe('a', func);
PubSub.subscribe('a.b', func);
PubSub.subscribe('a.b.c', func);

PubSub.clearSubscriptions('a.b');

PubSub.publish('a.b.c', { hello : 'world' });

// Would func still be notified of `a.b.c` topic?

[pvdz]

To be frank I had not considered hierarchical topics. But I suppose it would work the same way because, why not. If you unsubscribe a parent, like a.b in your example, it would make sense that any sub-topics would also be unsubscribed.

[mroderick]

I think that I am unlikely to use such a method myself, as I prefer to design parts of systems to not have too much knowledge about other parts of systems (so, in one part, I might not know if it would be safe to remove all subscriptions).

However, I think that with the right level of documentation, such a method could be useful in some scenarios.

[pvdz]

The use case could be cleanup of an app, removing all global-level listeners when they are no longer needed because the app served it's purpose.

[mroderick]

This has been implemented with #62, and is included in 1.5.0