build.clj

(require 'cljs.closure)                                                                                                                               
(require 'cljs.js-deps)                                                                                                                               
(import 'java.net.URLClassLoader)                                                                                                                     
(import 'java.net.URL)                                                                                                                                
                                                                                                                                                      
(def react-url                                                                                                                                        
  "https://clojars.org/repo/cljsjs/react/0.13.0-0/react-0.13.0-0.jar")                                                                                
                                                                                                                                                      
(defn add-url                                                                                                                                         
  "Act like pomegranate/dynapath and add a url onto the classpath"                                                                                    
  [cl url]                                                                                                                                            
  (-> URLClassLoader                                                                                                                                  
      (.getDeclaredMethod "addURL" (into-array Class [URL]))                                                                                          
      (doto (.setAccessible true))                                                                                                                    
      (.invoke cl (into-array URL [url]))))                                                                                                           
                                                                                                                                                      
(defn build-output                                                                                                                                    
  "Build the src tree and capture warnings"                                                                                                           
  []                                                                                                                                                  
  (with-out-str                                                                                                                                       
    (binding [*err* *out*]                                                                                                                            
      (cljs.closure/build                                                                                                                             
       "src"                                                                                                                                          
       {:output-to "out/main.js"}))))                                                                                                                 
                                                                                                                                                      
(assert                                                                                                                                               
 (= (build-output)                                                                                                                                    
    "WARNING: Required namespace not provided for cljsjs.react\n"))                                                                                     
                                                                                                                                                      
(let [cl (.. Thread currentThread getContextClassLoader)]                                                                                             
  (add-url cl (URL. react-url)))                                                                                                                      
                                                                                                                                                      
(assert                                                                                                                                               
 (= (build-output) ""))

core.cljs

(ns t.core                                                                                                                                            
  (:require cljsjs.react))                                                                                                                            
                                                                                                                                                      
(enable-console-print!)                                                                                                                               
                                                                                                                                                      
(println "Hello world!")

shell

java -cp cljs.jar:src clojure.main build.clj
Exception in thread "main" java.lang.AssertionError: Assert failed: (= (build-output) ""), compiling:(/home/xeqi/workspace/tmp/cljscompilerchck/build.clj:31:33)
	at clojure.lang.Compiler.load(Compiler.java:7142)
	at clojure.lang.Compiler.loadFile(Compiler.java:7086)
	at clojure.main$load_script.invoke(main.clj:274)
	at clojure.main$script_opt.invoke(main.clj:336)
	at clojure.main$main.doInvoke(main.clj:420)
	at clojure.lang.RestFn.invoke(RestFn.java:408)
	at clojure.lang.Var.invoke(Var.java:379)
	at clojure.lang.AFn.applyToHelper(AFn.java:154)
	at clojure.lang.Var.applyTo(Var.java:700)
	at clojure.main.main(main.java:37)
Caused by: java.lang.AssertionError: Assert failed: (= (build-output) "")
	at user$eval40.invoke(build.clj:33)
	at clojure.lang.Compiler.eval(Compiler.java:6703)
	at clojure.lang.Compiler.load(Compiler.java:7130)
	... 9 more