code: function addFlags(mask, flags) {
      if (flags.onlydir) mask = mask | Inotify.IN_ONLYDIR;
      if (flags.dont_follow) mask = mask | Inotify.IN_DONT_FOLLOW;
      if (flags.oneshot) mask = mask | Inotify.IN_ONESHOT;
      return mask;
  }
docs: Add additional flags to a given mask.  mask  - Number flags - Object  Returns a number.