Glogi DCE Demonstration

This repository produces a minimal working example of DCE failing with Glogi unless some modifications are made to a private log-expr function.

Getting started

If you are using Emacs, you can M-x cider-jack-in-cljs then choose the :demo build target. Once a REPL is opened, visit the following URLs in your web browser.

• http://localhost:9630
• http://localhost:8080

The first link is Shadow CLJS console. The second link is a webpage with very minimal layout and code.

Use the Shadow CLJS console to quickly switch between development and release builds and compare output. Unfortunately, Shadow CLJS must be restarted to try out the example code below with the modified Glogi library.

Example code

(defn ^:export init []
  (let [message (js/document.createElement "p")]
    (set! (.-innerText message)
          (if ^boolean goog.DEBUG
            "You are in a development build. Logging is expected."
            (str "You are in a release build.\n"
                 "Check the compiled JS file for traces of log strings.")))
    (js/document.body.appendChild message))
  (log/trace :message "You should not see me in your release build!"))

Release build output

Without modifications

 function eg() {
   var a = document.createElement("p");
   a.innerText = "You are in a release build.\nCheck the compiled JS file for traces of log strings.";
   document.body.appendChild(a);
   a = new kb(null,2,[Ke, "You should not see me in your release build!", Je, 13],null);
   if (w(!1))
     if (Af("demo.core"),
	  w(null)) {
	var b = Bb.h(dg, pf);
	a = new ("undefined" !== typeof aa && "undefined" !== typeof fa && "undefined" !== typeof fa.zb ? fa.zb : vf)(b,a,"demo.core");
	a = "undefined" !== typeof aa && "undefined" !== typeof qf && "undefined" !== typeof wf ? void 0 : null.kc(a)
     } else
	a = null;
   else
     a = null;
   return a
 }

With modifications

function eg() {
  var a = document.createElement("p");
  a.innerText = "You are in a release build.\nCheck the compiled JS file for traces of log strings.";
  document.body.appendChild(a);
  return null
}