Add force-update

src/reagent/core.cljs

@@ -160,6 +160,16 @@ Equivalent to (swap! (state-atom this) merge new-state)"
   (assert (or (nil? new-state) (map? new-state)))
   (swap! (state-atom this) merge new-state))
 
+(defn force-update
+  "Force a component to re-render immediately.
+
+  If the second argument is true, child components will also be
+  re-rendered, even is their arguments have not changed."
+  ([this]
+   (force-update this false))
+  ([this deep]
+   (util/force-update this deep)))
+
 
 (defn props
   "Returns the props passed to a component."

src/reagent/impl/util.cljs

@@ -137,3 +137,9 @@
   (doseq [v (vals @roots)]
     (apply re-render-component v))
   "Updated")
+
+(defn force-update [comp deep]
+  (if deep
+    (binding [*always-update* true]
+      (.' comp forceUpdate))
+    (.' comp forceUpdate)))

test/reagenttest/testreagent.cljs

@@ -516,3 +516,27 @@
          (rstr [:div.foo [:p.bar.foo [:b.foobar "xy"]]])))
   (is (= (rstr [:div>p.bar.foo>a.foobar {:href "href"} "xy"])
          (rstr [:div [:p.bar.foo [:a.foobar {:href "href"} "xy"]]]))))
+
+(deftest test-force-update
+  (let [v (atom {:v1 0
+                 :v2 0})
+        comps (atom {})
+        c1 (fn []
+             (swap! comps assoc :c1 (r/current-component))
+             [:p (swap! v update-in [:v1] inc)])
+        c2 (fn []
+             (swap! comps assoc :c2 (r/current-component))
+             [:p (swap! v update-in [:v2] inc)
+              [c1]])]
+    (with-mounted-component [c2]
+      (fn [c div]
+        (is (= @v {:v1 1 :v2 1}))
+
+        (r/force-update (:c2 @comps))
+        (is (= @v {:v1 1 :v2 2}))
+
+        (r/force-update (:c1 @comps))
+        (is (= @v {:v1 2 :v2 2}))
+
+        (r/force-update (:c2 @comps) true)
+        (is (= @v {:v1 3 :v2 3}))))))