iconv-lite

Stream-Api
return new Promise(async (resolve, reject) => {
    const response = await this.gotInstanse(url, gotOptions);

    const converterStream = iconv.decodeStream('win1251');
    const xmlStream = await this.gotInstanse.stream(url, gotOptions);

    xmlStream.pipe(converterStream);
    let xmlString = '';

    xmlStream
      .on('error', error => this.logger.error(error))
      .on('data', data => {
        xmlString += data;
      })
      .on('end', () => {
        if (parser.validate(xmlString) === true) {
          //optional (it'll return an object in case it's not valid)
          const jsonObj = parser.parse(xmlString, options);

          resolve(jsonObj);
        } else {
          reject({ error: 'format is not valid' });
        }
      });
  });

Buffer-Api
const { url, auth, login, password } = params;

  const gotOptions = auth ? { username: login, password } : {};

  const responsePromise = this.gotInstanse(url, gotOptions);
  const bufferPromise = responsePromise.buffer();

  try {
    const [response, buffer] = await Promise.all([responsePromise, bufferPromise]);
    let parseString = response.body;

    if (
      response.headers['content-type'].includes('windows-1251') ||
      response.headers['content-type'].includes('cp1251')
    ) {
      parseString = iconv.decode(buffer, 'win1251');
    }

    return parser.parse(parseString, options);
  } catch (err) {
    throw new Error(err);
  }