tempids.cljs

(ns frustration.core
  (:require [goog.dom :as gdom]
            [om.next :as om :refer-macros [defui]]
            [om.dom :as dom :include-macros true]))

(enable-console-print!)

(def init-data
  {:list [{:id1 "temp"}
          {:id1 "other"}
          {:id1 "etc"}]})

(defui ThingWithIdent
  static om/Ident
  (ident [this {:keys [id1]}]
    [:id2 id1])
  static om/IQuery
  (query [this]
    '[:id1])
  Object
  (render [this]
    (dom/div {} (str (:id1 (om/props this))))))

(def thing (om/factory ThingWithIdent {:keyfn :id1})) ; this has to be :id1 or things don't render right

(defui RootView
  static om/IQuery
  (query [this]
    [{:list (om/get-query ThingWithIdent)}])
  Object
  (render [this]
    (let [{:keys [list]} (om/props this)]
      (apply dom/div {} (map thing list)))))

(defmulti read om/dispatch)

(defmethod read :list
  [{:keys [state query] :as env} key params]
  (let [st @state]
    {:value (om/db->tree query (get st key) st)}))

(defmulti mutate om/dispatch)

(defmethod mutate 'app/tempids
  [{:keys [state]} _ {:keys [name]}]
  {})


;; :id2

(def reconciler2
  (om/reconciler {:state init-data
                  :id-key :id2 ; intuitively chose :id2 but this behaves badly
                  :parser (om/parser {:read read :mutate mutate})}))

(om/add-root! reconciler2
              RootView
              (gdom/getElement "app"))

(om/merge! reconciler2 {'app/tempids {:tempids {[:id2 "temp"] [:id2 "new"]}}})
(println @reconciler2)
;; => {:list [[:id2 temp] [:id2 other] [:id2 etc]],
;;     :id2 {temp {:id1 temp}, other {:id1 other}, etc {:id1 etc}}, 
;;     :om.next/tables #{:id2}}

(om/remove-root! reconciler2
                 (gdom/getElement "app"))

;; :id1

(def reconciler1
  (om/reconciler {:state init-data
                  :id-key :id1 ; not :id2
                  :parser (om/parser {:read read :mutate mutate})}))

(om/add-root! reconciler1
              RootView
              (gdom/getElement "app"))

(om/merge! reconciler1 {'app/tempids {:tempids {[:id2 "temp"] [:id2 "new"]}}})
(println @reconciler1)
;; => {:list [[:id2 new] [:id2 other] [:id2 etc]], 
;;     :id2 {new {:id1 new}, other {:id1 other}, etc {:id1 etc}}, 
;;     :om.next/tables #{:id2}}