re-frame go-swap effect: Push the result pulled from a channel into the db

handlers.clj

; Requires this event handler

(reg-event-db :db-swap
  (fn [db [_ func value]]
    (func db value)))

;The go-swap effect

(reg-fx :go-swap
  (fn [[func chan]]
    (go (dispatch [:db-swap func (<! chan)]))))


;
; Example Usage:
;

; Mark the start and end of an ajax request in local state.

(reg-event-fx :my-table-refresh
  (fn [cofx _]
    {:db (assoc-in (:db cofx) [:my-table :refreshing] true)
     :go-swap [
        (fn [db data] 
          (-> db
            (assoc-in [:my-table :refreshing] false)
            (assoc-in [:my-table :rows] data)))
        (go (<! (ajax-get! "/my-table/rows")))]}))


; Subscriptions can further be used to drive components to indicate an update is loading.

(reg-sub :is-table-refreshing
  (fn [db]
    (get-in db [:my-table :refreshing])))

; Example component

(defn refresh-button []
  (let [refreshing (subscribe [:is-table-refreshing])]
    (fn []
      [:div
        [:button
          (if @refreshing
            {:class "disabled"}
            {:on-click #(dispatch [:my-table-refresh])})
          "Refresh My Table"]])))

(defn matchmaking-table []
  (let [rows (subscribe [:my-table-rows])
        refreshing (subscribe [:is-table-refreshing])]
    (fn []
      [:div.matchmaking
        [:table
         [:tr
          [:th "Name"]
          [:th "Information"]
         (cond 
           (empty? @rows) [:td {:col-span "99"} "No things found."]
           @refreshing [:td {:col-span "99"} [:div.spinner "Loading"]]
           :else (for [row @matches] 
                      [build-row row]))]])))


(defn my-table-page []
  (fn []
    [base
     [refresh-button]
     [my-table]]))