fe: add bb task that treeshakes pico.min.css

- add a bb task that uses PurgeCSS to treeshake pico.min.css
- add a bb task that cleanly builds Bellsprout
- use purged pico css in Bellsprout
- write docs about Bellsprout

1 files changed, 33 insertions, 0 deletions

diff --git a/bellsprout/scripts/treeshake.clj b/bellsprout/scripts/treeshake.clj
new file mode 100644
index 0000000..6e9a786
--- /dev/null
+++ b/bellsprout/scripts/treeshake.clj
@@ -0,0 +1,33 @@
+#!/usr/bin/env bb
+(ns treeshake)
+
+(require '[babashka.tasks :refer [shell]])
+(require '[babashka.fs :as fs])
+(require '[cheshire.core :as json])
+
+(defn treeshake [content original target]
+  (let [shake (partial shell {:out :string}
+                 "purgecss" 
+                 "--css" original 
+                 "--content")
+        out (apply shake content)
+      css (-> out :out json/parse-string first (get "css"))]
+  (spit target css)))
+
+(def original-css "resources/public/css/pico.min.css")
+(def target-css "resources/public/css/pico.purged.css")
+(def html-file "resources/public/index.html")
+(def js-file "src/bellsprout/core.cljs")
+
+(defn treeshake-pico []
+  (treeshake [html-file js-file] original-css target-css)
+  (if (fs/exists? target-css)
+    (let [size #(.length (java.io.File. %))
+          old-size (size original-css)
+          new-size (size target-css)]
+      (println "Tree shaken. Purged CSS file size:" new-size "Bytes" 
+               (str "(" (- new-size old-size ) " Bytes)")))
+    (println "Something went wrong.")))
+
+(defn -main []
+  (treeshake-pico))