How to use the json2csv.AsyncParser function in json2csv

} catch (err) {
    console.error(err);
}

// Test convenience method "parse"
try {
    const csv = parse(data, opts);
    console.log(csv);
} catch (err) {
    console.error(err);
}

// Test for Asynchronous Parser
const transformOpts = { highWaterMark: 8192 };

const asyncParser = new AsyncParser(opts, transformOpts);

let csv = '';
asyncParser.processor
    .on('data', chunk => (csv += chunk.toString()))
    .on('end', () => console.log(csv))
    .on('error', err => console.error(err));

// Test for transform events
asyncParser.transform
    .on('header', header => console.log(header))
    .on('line', line => console.log(line))
    .on('error', err => console.log(err));

asyncParser.input.push(data); // This data might come from an HTTP request, etc.
asyncParser.input.push(null); // Sending `null` to a stream signal that no more data is expected and ends it.

export const transform = (parserOpts = {}) => observable => {
  // XXX: the parser wants to add a newline to everything we push to it for
  // some reason. likely "user error"
  const parser = new AsyncParser(
    {...parserOpts, eol: '', flatten: true},
    {
      objectMode: true
    }
  );
  return observable.pipe(
    finalize(() => {
      parser.input.push(null);
    }),
    tap(row => {
      parser.input.push(row);
    }),
    concatMapTo(fromEvent(parser.processor, 'data')),
    takeUntil(fromEvent(parser.processor, 'end')),
    filter(Boolean),
    map(_.pipe(_.trim, stripAnsi))

export const toCsv = (parserOpts = {}, streamOpts = {}) => observable => {
  const parser = new AsyncParser(parserOpts, {...streamOpts, objectMode: true});
  return observable.pipe(
    finalize(() => {
      parser.input.push(null);
    }),
    tap(row => {
      parser.input.push(row);
    }),
    concatMapTo(fromEvent(parser.processor, 'data')),
    takeUntil(fromEvent(parser.processor, 'end')),
    map(_.trimEnd)
  );
};