ClojureScript, Om and Core.async: How to handle events properly

Question

I have had a look at using Om for rich client website design. This also is my first time using core.async. Reading the tutorial https://github.com/swannodette/om/wiki/Basic-Tutorial I have seen the usage of a core.async channel to handle the delete operation (as opposed to doing all the work in the handler). I was under the impression that using that channel for deletion was merely done because the delete callback was declared in a scope where you have a cursor on an item-level where you actually want to manipulate the list containing that item.

To get more insights into channels I have seen Rich Hickey's talk http://www.infoq.com/presentations/clojure-core-async where he explains how its a good idea to use channels to get application logic out of event-callbacks. This made me wonder whether the actual purpose of the delete channel in the tutorial was to show that way of structuring an application. If so,

• what are best practices associated with that pattern?

• Should one create individual channels for all kinds of events? I.e. If I add a controller to create a new event, would I also create a new channel for object creations that is then used to get objects to be added to the global state at another place in the application?

• Lets say I have a list of items, and one items has a detailed/concise state flag. If detailed? is true it will display more information, if detailed? is false it will display fewer information. I have associated a on-click event that uses om/transact! on the cursor (being a view to the list item within the global state object).

(let [toggle-detail-handler 
      (fn [e]
        (om/transact! (get-in myitem [:state])
                      #(conj % {:detailed? (not (:detailed? %))})))]
  (html [:li {:on-click toggle-detail-handler}
         "..." ])) 

I realize that this might be a very succinct snippet where the overall benefit of using channels as a means to decouple the callback event from the acutal logic changes does at first not seem worth the effort but the overall benefits with more complex examples outweigh this. But on the other hand introducing an extra channel for such detail-not-detailed toggling seems to add a fair amount of load to the source code as well.

It would be great if you could give some hints/tips or other thoughts on the whole design issue and put them into perspective. I feel a little lost there.