new_contents: import re
  
  reexpr = r"""
      (                               # Capture code
          (?:
              "(?:\\.|[^"\\])*"           # String literal
              |
              '(?:\\.|[^'\\])*'           # String literal
              |
              (?:[^/\n"']|/[^/*\n"'])+    # Any code besides newlines or string literals (essentially no comments)
              |
              \n                          # Newline
          )+                          # Repeat
      )|
      (/\*  (?:[^*]|\*[^/])*   \*/)   # Multi-line comment
      |
      (?://(.*)$)                     # Comment
  """
  rx = re.compile(reexpr, re.VERBOSE + re.MULTILINE)
  
  # This regex matches with three different subgroups. One for code and two for comment contents. Below is a example of how to extract those.
  
  code = r"""// this is a comment
  var x = 2 * 4 // and this is a comment too
  var url = "http://www.google.com/" // and "this" too
  url += 'but // this is not a comment' // however this one is
  url += 'this "is not a comment' + " and ' neither is this //" // only this
  
  bar = 'http://no.comments.com/' // these // are // comments
  bar = 'text // string \' no // more //\\' // comments
  bar = 'http://no.comments.com/' /*
  multiline */
  bar = /var/ // comment
  
  /* comment 1 */
  bar = open() /* comment 2 */
  bar = open() /* comment 2b */// another comment
  bar = open( /* comment 3 */ file) // another comment
  """
  
  parts = rx.findall(code)
  print('*' * 80, '\nCode:\n\n',                  ''.join(x[0].strip(' ') for x in parts))
  print('*' * 80, '\nMulti line comments:\n\n', '\n'.join(x[1] for x in parts if x[1].strip()))
  print('*' * 80, '\nOne line comments:\n\n',   '\n'.join(x[2] for x in parts if x[2].strip()))
  
subject: Add a (weird) test file for testing the javascript comment stripping