For ClojureScript we have special parsing of :require to determine top-level Node dependencies, however this is not done for classpath lib files.
If both ClojureScript and ES6 classpath libs try to require a node_module we get the following exception:
`
Exception in thread "main" java.lang.IllegalArgumentException: Duplicate module path after resolving: /Users/davidnolen/development/clojure/hello-es6/node_modules/react/react.js
at com.google.javascript.jscomp.deps.ModuleLoader.resolvePaths(ModuleLoader.java:294)
at com.google.javascript.jscomp.deps.ModuleLoader.<init>(ModuleLoader.java:96)
at com.google.javascript.jscomp.Compiler.parseInputs(Compiler.java:1760)
at com.google.javascript.jscomp.Compiler.parse(Compiler.java:994)
`