Extending Closure Classes From Clojurescript. Original source: http://www.50ply.com/blog/2012/07/08/extending-closure-from-clojurescript/

editor_plugin.cljs

(ns frontend.editor-plugin
  (:require-macros [frontend.goog-extend :refer [goog-extend]])
  (:import [goog.editor Plugin]))

; 4. Now the code should work with advanced compilation but Closure Compiler
; will display few warnings about using "this" in static functions.
; To fix this, the constuctor should have proper JSDoc comments:
(goog-extend ^{:jsdoc ["@constructor" "@extends {goog.editor.Plugin}"]} FooPlugin Plugin
  ([]
    ; 1. This doesn't work with advanced compilation as Closure compiler checks that first
    ; parameter to goog/base is named "this" and Clojurescript compiler will name it "this$"
    ; (this-as this (goog/base this))
    ; 2. This doesn't seem to work for advanced compilation, "this" gets renamed?
    ; (goog/base (js* "this"))
    ; 3. Instead of calling goog/base, it's possible to call base class constructor
    ; directly (Closure Library code is doing this)
    (this-as this (.call Plugin this))
    )
  ...)

goog_extend.clj

(ns frontend.goog-extend)

(defn- to-property [sym]
  (symbol (str "-" sym)))

(defmacro goog-extend [type base-type ctor & methods]
  `(do
     (def ~type (fn ~@ctor))

     (goog/inherits ~type ~base-type)

     ~@(map
        (fn [method]
          `(set! (.. ~type -prototype ~(to-property (first method)))
                 (fn ~@(rest method))))
        methods)))