code: function convertCookie (value, converter) {
    if (value.indexOf('"') === 0) {
      // this is a quoted cookied according to RFC2068
      // remove enclosing quotes and internal quotes and backslashes
      value = value.slice(1, -1).replace(/\\"/g, '"').replace(/\\\\/g, '\\');
    }
  
    let parsedValue;
    try {
      parsedValue = decodeURIComponent(value.replace(/\+/g, ' '));
    } catch (e) {
      // no need to fail if we can't decode
      log.warn(e);
    }
  
    return converter ? converter(parsedValue) : parsedValue;
  }
docs: parses the value if needed and converts the value if a converter is provided internal function, not exported