code: function stringToFlockFlags(flag) {
    // Only mess with strings
    if (typeof flag !== 'string') {
      return flag;
    }
    switch (flag) {
      case 'sh':
        return binding.LOCK_SH;
  
      case 'ex':
        return binding.LOCK_EX;
  
      case 'shnb':
        return binding.LOCK_SH | binding.LOCK_NB;
  
      case 'exnb':
        return binding.LOCK_EX | binding.LOCK_NB;
  
      case 'un':
        return binding.LOCK_UN;
  
      default:
        throw new Error('Unknown flock flag: ' + flag);
    }
  }
docs: Used by flock