How to use highland

// reply with stream helper
const replyWithStream = dataArr => {
 const replyStream = _();
 dataArr.forEach(data => replyStream.write(JSON.stringify(data)));
 replyStream.end('');
 return [200, new Readable().wrap(replyStream)];
}

 let result = {};
 const stream = _(tarStream.pipe(got.stream.post(remoteUrl, options)))
  .split()
  .filter(l => l && l.length);
 stream.on('data', str => {
  if (spinner) {
   spinner.text = 'Project uploaded! Waiting for deployment..';
 stream.on('end', () => {
 stream.on('error', e => (error = e));
})

folderToDocuments(linksPath)
 .each(result => {
  index.addDoc(result);
 })
 .done(() => {
  const indexJSON = index.toJSON();
  fs.writeFile(indexPath, JSON.stringify(indexJSON), () => {
   console.log('Successfully saved index!');
  });
 });

_(readDir(linksPath))
  .map(arr => arr.sort((a, b) => a.localeCompare(b)))
  .flatMap(arr => _(arrayMod(arr)))
  .flatMap(filepath => exports.fileToContent(filepath, linksPath))
  .flatMap(file => exports.fileToDocuments(file))

folderToDocuments(linksPath).toArray(data => {
 fs.writeFile(dataPath, JSON.stringify(data), () => {
  console.log('Successfully saved data!');
 });
});

_(readFile(filePath)).map(res => ({filename, text: res.toString()}))

_(sections)
  .map(section => section.replace(/\r/g, ''))
  .filter(section => section && section.length > 0 && section.replace(/\n/g, '').length > 0)
  .map(text => ({text, filename}))
  .flatMap(({text, filename}) => {
   const [, episodeName] = /\d+-\d+-(.+?)\./.exec(filename);
   const [name, linksText] = text.split(/:\n/g);
   if (!linksText) {
    console.error('Error processing file:', filename, 'section:', text);
    return _([]);
   return _(links)
    .filter(l => l && l.length > 0)
    .map(link => {
     const urls = extractLinks(link);
     const title = link
    });
  })
  .filter(result => result)

const run = async () => {
 await folderToDocuments(linksPath, {arrayMod})
  .each(result => index.addDoc(result))
  .toPromise(Promise);
 console.log('Successfully generated index!');
 let shouldThrow = false;
 const res = await fileToContent(lastFile, linksPath)
  .flatMap(content => fileToDocuments(content))
  .flatMap(doc => {
   const titleRes = findInTitles(doc.title, index);
   const urlsRes = findInUrls(doc.urls, index);
    return _([]);
   };
   return _([possibleDuplicate]);
  })
  .filter(result => result)
  .each(duplicate => {
   if (duplicate.levels.includes('error')) {
    shouldThrow = true;
  .done(() => {
   if (shouldThrow) {
    throw new Error('Possible duplicate detected!');