docs: def list_js_files(dir):
      """
      Generator for all JavaScript files in the directory, recursively
  
      >>> 'examples/module.js' in list(list_js_files('examples'))
      True
  
      """
      for dirpath, dirnames, filenames in os.walk(dir):
          for filename in filenames:
              if is_js_file(filename):
                  yield os.path.join(dirpath, filename)