Behavioral objects for hub runner

[EyalAr]

Have support in the hub for custom behaviours of handlers based on returned types.

Imagine this could work:

// Widget 1:
define([
    "troopjs-widget/component"
], function (Widget) {
    return Widget.extend({
        "hub/topic": function(){
            return Aggregate("FOO");
        }
    });
});

// Widget 2:
define([
    "troopjs-widget/component"
], function (Widget) {
    return Widget.extend({
        "hub/topic": function(){
            return Aggregate("BAR");
            // Aggregate is a custom return type which
            // aggregates return values of all handlers of this hub topic.
        }
    });
});

// Service:
define([
    "troopjs-core/component/gadget",
    "troopjs-core/pubsub/hub"
], function (Gadget, hub) {
    return Gadget.extend({
        "sig/start": function(){
            return hub.publish("topic").then(function(data){
                // 'data' is an aggregation of the return values of
                // all the handlers for this topic
                console.log(data); // ["FOO", "BAR"]
            });
        }
    });
});

[mikaelkaron]

How would one indicate to the runner that the return is of a behavior type?

My personal feeling is that instead of having a registry (the first thing that jumped into my mind) we should have a way of ducktyping behavior enabled return values. This would reduce the amount of boilerplate needed and would probably be efficient enough.

Remember that this is somewhat hot code (every handler for any message passed).

Also, in what runners do we need this? From my understanding only the hub runner would need this.