Question

我想进入ClojureScript和Om。有一个特定的案例让我在圈子里跑。

我有一个首先没有键的组件。

(defn model-view [data owner]
  (reify
    om/IWillMount
    (will-mount [_]
      (om/transact! data [:stats] (fn [] {}))
      (go
        (let [response ((<! (api/get-stats (data :id))) :body)
              stats (:stats response)]
          (om/update! data [:stats] stats))))
    om/IRender
    (render [_]
      (dom/div nil
               (dom/h3 nil (data :title))
               ;; Here I want to use the :stats key in data that I
               ;; queried for in IWillMount, but its not present
               ;; the first time this model is rendered. It's only present
               ;; AFTER IWillMount has ran.
               (om/build model-stats-view (data :stats)))))

第一次调用此组件时，:stats中的data键根本不存在。这就是我进行API调用以获取其统计数据的原因。但是React仍然调用render函数，因此组件崩溃。

如何在此组件中设置初始状态，为data提供一个名为:stats的空地图，从而阻止尝试在nil调用中呈现(om/build model-stats-view)？< / p>

Answer 1

我更喜欢在init-state中执行所有初始化，然后在render-state中访问它。我在我的装载中放了一个循环。当您在go循环中更新init-state（即：e-map）时，它会强制调用渲染/重新呈现组件。我在所有组件中使用它来进行组件间/组件内消息传递。只需将某些东西推入酒吧/子频道，我们即可参加比赛。

;To update my state I use a function:

(defn set-owner-state! [owner old-map-key old-map new-map]
   (om/set-state! owner {old-map-key (merge old-map new-map)}))

om/IInitState
(init-state [_]
  (println "queue->init-state")
  {:e-map {:active-fsm nil}})

om/IDidMount
(did-mount [_]
    (go-loop []
        (let [[v _] (alts! [server-fsm-events dispatcher-events])
              current-state (om/get-state owner)
              e-map (:e-map current-state)]
        ; what goes in here is the logic to respond to a message
        ; in my case I have a match, it could be a cond or a set of
        ; if's.
        (set-owner-state! owner :e-map e-map {:active-fsm :active :task-paths nil})
    ...

om/IRenderState
(render-state [_ {:keys [e-map]}]
  (println "e-map:" e-map)
  ...

设置组件数据中缺失键的初始状态

1 个答案: