Add a little demo

.gitignore

@@ -1,6 +1,6 @@
 index.html
 assets/
-news/
+/news/
 target
 pom.xml
 .lein-repl-history

demo/reagentdemo/common.cljs

@@ -21,9 +21,7 @@
 ")
 
 (defn src-for-names [srcmap names]
-  (string/join "\n" (-> srcmap
+  (string/join "\n" (map srcmap names)))
-                        (select-keys names)
-                        vals)))
 
 (defn fun-map [src]
   (-> src src-parts src-defs (assoc :ns nssrc)))
@@ -36,7 +34,7 @@
     (fn []
       [:div
        (when comp
-         [:div.demo-example
+         [:div.demo-example.clearfix
           [:a.demo-example-hide {:on-click (fn [e]
                                              (.preventDefault e)
                                              (swap! showing not)
@@ -48,6 +46,6 @@
               [:div.simple-demo [comp]]
               [comp]))])
        (when @showing
-         [:div.demo-source
+         [:div.demo-source.clearfix
           [:h3.demo-heading "Source"]
           src])])))

demo/reagentdemo/news.cljs

@@ -4,6 +4,7 @@
             [reagentdemo.syntax :refer-macros [get-source]]
             [reagentdemo.page :refer [title link page-map]]
             [reagentdemo.common :as common :refer [demo-component]]
+            [reagentdemo.news.async :as async]
             [todomvc :as todomvc]))
 
 (def funmap (-> "reagentdemo/news.cljs" get-source common/fun-map))
@@ -81,7 +82,9 @@
       [undo-demo-cleanup]]]))
 
 (defn main []
-  [undo-example])
+  [:div
+   [async/main]
+   [undo-example]])
 
 (swap! page-map assoc
        "news/cloact-reagent-undo-demo.html" undo-example)

demo/reagentdemo/news/async.cljs

@@ -0,0 +1,106 @@
+(ns reagentdemo.news.async
+  (:require [reagent.core :as reagent :refer [atom]]
+            [reagent.debug :refer-macros [dbg println]]
+            [reagentdemo.syntax :refer-macros [get-source]]
+            [reagentdemo.page :refer [title link page-map]]
+            [reagentdemo.common :as common :refer [demo-component]]))
+
+(def funmap (-> "reagentdemo/news/async.cljs" get-source common/fun-map))
+(def src-for (partial common/src-for funmap))
+
+(defn timing-wrapper [{f :component-fn}]
+  (let [start-time (atom nil)
+        render-time (atom nil)
+        now #(.now js/Date)
+        start (fn [] (reset! start-time (now)) nil)
+        stop #(reset! render-time (- (now) @start-time))
+        timed-f (with-meta f
+                  {:get-initial-state start
+                   :component-will-update start
+                   :component-did-mount stop
+                   :component-did-update stop})]
+    (fn [props children]
+      [:div
+       [:p [:em "render time: " @render-time "ms"]]
+       (into [timed-f props] children)])))
+
+(def base-color (atom {:red 130 :green 160 :blue 120}))
+(def ncolors (atom 20))
+(def random-colors (atom nil))
+
+(defn to-rgb [{:keys [red green blue]}]
+  (let [hex (fn [x]
+              (str (if (< x 16) "0")
+                   (-> x js/Math.round (.toString 16))))]
+    (str "#" (hex red) (hex green) (hex blue))))
+
+(defn tweak-color [{:keys [red green blue]}]
+  (let [rnd #(-> (js/Math.random) (* 256))
+        tweak #(-> % (+ (rnd)) (/ 2) js/Math.floor)]
+    {:red (tweak red) :green (tweak green) :blue (tweak blue)}))
+
+(defn reset-random-colors []
+  (reset! random-colors
+          (repeatedly #(-> @base-color tweak-color to-rgb))))
+
+(defn color-choose [{color-part :color-part}]
+  [:div (name color-part) " " (color-part @base-color)
+   [:input {:type "range" :min 0 :max 255
+            :style {:width "100%"}
+            :value (color-part @base-color)
+            :on-change
+            (fn [e]
+              (swap! base-color assoc
+                     color-part (-> e .-target .-value int))
+              (reset-random-colors))}]])
+
+(defn ncolors-choose []
+  [:div
+   "number of colors " @ncolors
+   [:input {:type "range" :min 0 :max 500
+            :style {:width "100%"}
+            :value @ncolors
+            :on-change #(reset! ncolors (-> % .-target .-value))}]])
+
+(defn color-plate [{color :color}]
+  [:div.color-plate
+   {:style {:background-color color}}])
+
+(defn palette []
+  (let [color @base-color
+        n @ncolors]
+    [:div
+     [:div
+      [:p "base color: "]
+      [color-plate {:color (to-rgb color)}]]
+     [:div.color-samples
+      [:p n " random matching colors:"]
+      (map-indexed (fn [k v]
+                     [color-plate {:key k :color v}])
+                   (take n @random-colors))]]))
+
+(defn color-demo []
+  (reset-random-colors)
+  (fn []
+    [:div
+     [:h2 "Matching colors"]
+     [color-choose {:color-part :red}]
+     [color-choose {:color-part :green}]
+     [color-choose {:color-part :blue}]
+     [ncolors-choose]
+     [timing-wrapper {:component-fn palette}]]))
+
+(defn main []
+  [:div.reagent-demo
+   [title "Reagent: Faster by waiting"]
+   [:h1 [link {:href main} "Faster by waiting"]]
+
+   [demo-component {:comp color-demo
+                    :src (src-for
+                          [:ns :timing-wrapper :base-color
+                           :ncolors :random-colors :to-rgb
+                           :tweak-color :reset-random-colors :color-choose
+                           :ncolors-choose :palette :color-demo])}]])
+
+(swap! page-map assoc
+       "news/reagent-is-async.html" main)

demo/reagentdemo/page.cljs

@@ -78,10 +78,16 @@
                             identity))
            children)))
 
+(add-watch page ::title-watch
+           (fn [_ _ _ p]
+             ;; First title on a page wins
+             (reset! title-atom "")))
+
 (defn title [props children]
   (let [name (first children)]
+    (when (= @title-atom "")
       (if reagent/is-client
         (let [title (aget (.getElementsByTagName js/document "title") 0)]
           (set! (.-innerHTML title) name)))
-    (reset! title-atom name)
+      (reset! title-atom name))
     [:div]))

site/demo.css

@@ -5,6 +5,16 @@
     box-sizing: border-box;
 }
 
+
+.clearfix:before, .clearfix:after {
+    content: " ";
+    display: table;
+}
+
+.clearfix:after {
+    clear: both;
+}
+
 div.nav {
     position: absolute;
     top: 0;
@@ -140,3 +150,16 @@ ul.nav > li.brand > a {
     float: right;
     cursor: pointer;
 }
+
+/* Color demo */
+
+.color-plate {
+    float: left;
+    height: 100px;
+    width: 100px;
+}
+
+.color-samples {
+    clear: both;
+    padding-top: 0.5em;
+}