     "bower_components/socket.io-client/dist/socket.io.js"
   ]
 
+  all_2d_files = files_2d.concat(extras)
+  all_3d_files = files_3d.concat(extras)
+
+  for file in all_3d_files.concat(all_2d_files)
+    unless fs.existsSync(file)
+      throw "ERROR: #{file} does not exist!"
+
   grunt.initConfig
     pkg: grunt.file.readJSON("package.json")
     shell:

module.exports = (grunt) ->
  files_3d = [
    "bower_components/stats.js/src/Stats.js"

          mangle: false
          beautify: true
        files: [
          "build/coffee-engine-2d.js": all_2d_files
          "build/coffee-engine-3d.js": all_3d_files
        ]

  grunt.registerTask "compile:coffee:watch", ["shell:compile-coffee-watch"]
