Parse require calls from JS files using Closure

build.boot

@@ -1,5 +1,6 @@
 (set-env!
-  :dependencies '[[cheshire "5.6.3"]]
+  :dependencies '[[cheshire "5.6.3"]
+                  [com.google.javascript/closure-compiler-unshaded "v20160911"]]
   :source-paths #{"src"})
 
 (require '[cljsjs.npm.build :refer [package]])

src/cljsjs/closure.clj

@@ -0,0 +1,40 @@
+(ns cljsjs.closure
+  (:require [clojure.java.io :as io])
+  (:import [com.google.javascript.jscomp CompilerPass NodeTraversal
+            CompilerOptions SourceFile NodeTraversal$Callback JSModule]
+           [com.google.javascript.rhino Node]))
+
+(defn is-require? [n]
+  (and (= 2 (.getChildCount n))
+       (.. n getFirstChild (matchesQualifiedName "require"))
+       (.. n getSecondChild isString)))
+
+(defn is-npm-require? [module-name]
+  false)
+
+(defn finder [requires]
+  (reify NodeTraversal$Callback
+    (shouldTraverse ^boolean [this t n parent]
+      true)
+    (visit ^void [this t n parent]
+      (if (is-require? n)
+        (swap! requires conj  (.. n getSecondChild getString)))
+      nil)))
+
+(defn process-pass [compiler requires]
+  (reify CompilerPass
+    (process [this _ root]
+      (NodeTraversal/traverseEs6 compiler root (finder requires)))))
+
+(defn find-requires [f]
+  (let [requires (atom [])
+        module (doto (JSModule. "$singleton$")
+                 (.add (SourceFile/fromFile f)))
+        closure-compiler (com.google.javascript.jscomp.Compiler.)
+        pass (process-pass closure-compiler requires)]
+    (doseq [input (.getInputs module)]
+      (.process pass nil (.getAstRoot input closure-compiler)))
+    @requires))
+
+(comment
+  (find-requires (io/file "node_modules/react/lib/React.js")))

src/cljsjs/npm/build.clj

@@ -2,6 +2,7 @@
   (:require [cheshire.core :as json]
             [clojure.java.io :as io]
             [clojure.string :as string]
+            [cljsjs.closure :as closure]
             [boot.util :as util]
             [boot.core :as boot]
             [boot.task.built-in :as built-in]))