Small fixes and feature experiment

src/zero/component.cljs

@@ -25,6 +25,9 @@ Implements web components.  Require this ns to enable them.
 (def ^:private JS-UNDEFINED (js* "undefined"))
 (def ^:private RENDER-ORDER-SYM (js/Symbol "zRenderOrder"))
 
+(def before-render-sig (Signal. ::before-render))
+(def after-render-sig (Signal. ::after-render))
+
 (defn- default-ns
   [tag]
   (case tag
@@ -422,6 +425,7 @@ Implements web components.  Require this ns to enable them.
 (defn- render
   []
   (reset! !render-frame-id nil)
+  (before-render-sig)
   (while (seq @!dirty)
     (let [batch @!dirty]
       (reset! !dirty #{})
@@ -472,7 +476,8 @@ Implements web components.  Require this ns to enable them.
                   (when (contains? observed-events event-type)
                     (.dispatchEvent shadow (js/Event. event-type #js{:bubbles false})))
                   (when (contains? observed-events "render")
-                    (.dispatchEvent shadow (js/Event. "render" #js{:bubbles false}))))))))))))
+                    (.dispatchEvent shadow (js/Event. "render" #js{:bubbles false})))))))))))
+  (after-render-sig))
 
 (defn- request-render
   [^js/Node dom]

src/zero/dom.cljs

@@ -4,6 +4,7 @@
    [zero.impl.base :refer [IDisposable dispose!]]
    [zero.config :as config]
    [zero.core :refer [<< <<ctx act]:as z]
+   [zero.extras.db :as db] ;; not supposed to use 'extras' in core modules, big changes coming, this is temporary
    [clojure.string :as str]
    [goog.object :as gobj]))
 
@@ -31,12 +32,19 @@
     (reset! !state new-state)
     (throw (ex-info "No internal state available on given DOM node" {:dom dom}))))
 
+(defn patch-internal-state
+  [^js/Node dom patch]
+  (if-let [!state (gobj/get dom INTERNAL-STATE-SYM)]
+    (swap! !state (comp first db/apply-patch) patch)
+    (throw (ex-info "No internal state available on given DOM node" {:dom dom}))))
+
 (config/reg-effects
   ::listen listen
   ::unlisten unlisten
   ::bind bind
   ::unbind unbind
-  ::set-internal-state set-internal-state)
+  ::set-internal-state set-internal-state
+  ::patch-internal-state patch-internal-state)
 
 (config/reg-injections
   ::select-doms

src/zero/impl/actions.cljs

@@ -5,6 +5,7 @@
     [goog.object :as gobj]
     [goog :refer [DEBUG]]
     [zero.config :as config]
+    [zero.impl.signals :as sig]
     [zero.logger :as log]))
 
 (defonce Action (js* "
@@ -106,7 +107,25 @@
          (actually-perform!)
 
          :default
-         (js/setTimeout actually-perform!))
+         (js/setTimeout actually-perform!)
+
+         :after-render
+         (when-let [after-render-sig (some-> (resolve 'zero.component/after-render-sig) deref)]
+           (let [k (gensym)]
+             (sig/listen after-render-sig k
+               (fn []
+                 (sig/unlisten after-render-sig k)
+                 (actually-perform!))
+               nil)))
+
+         :before-render
+         (when-let [before-render-sig (some-> (resolve 'zero.component/before-render-sig) deref)]
+           (let [k (gensym)]
+             (sig/listen before-render-sig k
+               (fn []
+                 (sig/unlisten before-render-sig k)
+                 (actually-perform!))
+               nil))))
        nil)))
 
   IEquiv