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add loading? fn to check if a view-cursor is waiting for initial data

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Gered 2016-05-23 15:15:23 -04:00
parent 2936d92938
commit e86ab23603
2 changed files with 28 additions and 6 deletions
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26
reagent-data-views/src/reagent_data_views/client/component.cljs
View file

@ -2,8 +2,9 @@
(:require
[clojure.set :refer [difference]]
[reagent.core :as r]
[reagent.ratom :refer [RCursor]]
[reagent.impl.component :refer [reagent-component?]]
[reagent-data-views.client.core :as views]
[reagent-data-views.client.core :as rdv]
[reagent-data-views.client.utils :refer [update-component-state!]]))
(defn unsubscribe-all!
@ -12,7 +13,7 @@
[this]
(assert (reagent-component? this))
(let [last-used-view-sigs (:last-used-view-sigs (r/state this))]
(views/unsubscribe! last-used-view-sigs)
(rdv/unsubscribe! last-used-view-sigs)
(update-component-state! this #(dissoc % :used-view-sigs :last-used-view-sigs))))
(defn prepare-for-render!
@ -38,7 +39,7 @@
(if (not= used-view-sigs last-used-view-sigs)
(let [sigs-to-unsub (vec (difference last-used-view-sigs used-view-sigs))
sigs-to-sub (vec (difference used-view-sigs last-used-view-sigs))]
(views/update-subscriptions! sigs-to-sub sigs-to-unsub)
(rdv/update-subscriptions! sigs-to-sub sigs-to-unsub)
(r/set-state this {:used-view-sigs #{}
:last-used-view-sigs used-view-sigs})))))
@ -61,4 +62,21 @@
this (r/current-component)]
(assert (not (nil? this)) "view-cursor can only be used within a defvc component's render function.")
(update-component-state! this #(update-in % [:used-view-sigs] conj view-sig))
(views/->view-sig-cursor view-sig)))
(rdv/->view-sig-cursor view-sig)))
(defn loading?
"Returns true if the given view-cursor is still waiting for initial data
to be received from the server. Once that first set of data is received,
this function will always return false and cannot be used to e.g. check
if an updated set of data is waiting to be received."
[view-cursor]
(if (instance? RCursor view-cursor)
(let [[view-sig & _] (.-path view-cursor)
cursor (r/cursor rdv/view-data [view-sig])]
; if even :refcount is missing, it means that this is the first render
; of the component where the view-cursor was created (a subscription
; request has not even been sent to the server yet, so :loading? has
; not yet been set yet). once the component's first render is finished,
; :loading? will be set as we expect.
(boolean (or (not (:refcount @cursor))
(:loading? @cursor))))))

8
reagent-data-views/src/reagent_data_views/client/core.cljs
View file

@ -29,8 +29,11 @@
(r/cursor view-data [view-sig :data]))
(defn- handle-view-refresh [view-sig data]
(let [cursor (->view-sig-cursor view-sig)]
(reset! cursor data)))
(let [cursor (r/cursor view-data [view-sig])]
(swap! cursor
#(-> %
(dissoc :loading?)
(assoc :data data)))))
(defn subscribed?
"Returns true if we are currently subscribed to the specified view."
@ -66,6 +69,7 @@
; a standard view refresh when the subscription is processed
(if-not refcount
(assoc vd view-sig {:refcount 1
:loading? true
:data nil})
(update-in vd [view-sig :refcount] inc))))))