Clojurescript protocol usage?

Taking a first stab at using protocols in ClojureScript. Following is the protocol definition/implementation:

(defprotocol IDataTable
  (-pages [this])
  (-cnt! [this cnt])
  (-paginate [this])
 )

(deftype DataTable [id url info]
 IDataTable
 (-cnt! [_ cnt] (swap! info (fn [v] (assoc v :cnt cnt))) )
 (-pages [_]
   (inc (.round js/Math (/ (:cnt @info) (:length @info))))
 )

(-paginate [_]
  (let [arr (take 5 (drop (- (:page @info) 1) (range 1 (pages))))]
   (c/paging id (flatten ["Prev" arr "Next"]) )
  ))
 )

I am confused on how to invoke the functions defined in the protocol.

Following is the code to instantiate:

(def table-id "some-table")
(def paging (atom {:page 1 :length 10 :cnt 0  }))
(def data-table (DataTable. table-id "/list/data" paging))

The above code works and can access the properties using the following form:

(js/alert (.-id data-table))

The problem I am facing is how to invoke the functions defined in the protocol. The following forms result in error (runtime).

 (-cnt! data-table 10) ;; Error: -cnt! is not a method
 (.-cnt! data-table 10) ;; Error

Browsed the generated Javascript code, its got long-winded names for functions.

Thanks

EDIT: Think I found the answer. Looks like I need supporting functions in the namespace.

(defn cnt! [t cnt]
   (when (satisfies? IDataTable t)
     (-cnt! t cnt))
 )

With the function defined above, am able to access the functions. Wonder if this is the right approach?

EDIT2: Well, with further analyzing the generated javascript code realized one doesn't need helper functions as the above edit, the function calls needs to prefixed with namespace:

 (:require [table :as tbl])

(def table-id "some-table")
(def paging (atom {:page 1 :length 10 :cnt 0  }))
(def data-table (DataTable. table-id "/list/data" paging))

 (tbl/-cnt! data-table 10) ;; Works!!!