In #791 the consesus was that how to create classes should be on wiki.

Style-Guide.md

@@ -0,0 +1,16 @@
+# Style Guide
+## Classes
+The standard way of creating classes in pdf.js is the following. Please note that by class we mean an object that is class-like.
+<pre>
+var Name = (function NameConstructor() {
+  function Name(name) {
+    this.name = name;
+  }
+
+  Name.prototype = {
+  };
+  ...
+
+  return Name;
+})();
+</pre>