How to use the i18next-scanner.Parser function in i18next-scanner

function i18nScanner(params) { // eslint-disable-line
  const parser = new Parser({
    keySeparator: '>',
    nsSeparator: '|',
  });

  const sourceJSON = fs.readFileSync(params.outputFilePath, 'utf8');
  let translationsSource;
  try {
    translationsSource = JSON.parse(sourceJSON);
  } catch (e) {
    process.stderr.write(`i18nScanner: ${e}\n`);
    return;
  }

  const customHandler = function (key, options) {
    const value = translationsSource[key] || key;
    if (options.context) {

function parse(config, oldTranslations) {
  const parser = new Parser({
    keySeparator: '>',
    nsSeparator: '|',
  });

  config.files
    .map(filePattern => glob.sync(filePattern, {}))
    .reduce((accumulator, files) => [...accumulator, ...files], [])
    .forEach(file => {
      const content = fs.readFileSync(file, 'utf-8');
      parser.parseFuncFromString(
        content,
        { list: config.translationFunctionNames },
        (key, options) => customHandler(parser, oldTranslations, key, options)
      );
    });