api.js

const spawnedProcess = spawn('python3', ['./python/pdfConverter.py'])
var referenceJson = { turfs: [] }

spawnedProcess.stderr
  .on('data', (data) => {
    console.log(`error:${data}`);
    res.sendStatus(500)
  })
  .on('close', () => {
    try {
      createInterface({
        input: createReadStream('./python/voterfiles/canvass.csv', 'utf8'),
        crlfDelay: Infinity
      }).on('line', (line) => {
        let { turfs } = referenceJson
        const parsedLine = line.split(','),
          voter = {
            'name': parsedLine[0],
            'id': parsedLine[1],
            'firstName': parsedLine[3].replace('\'', '').trimLeft(),
            'lastName': parsedLine[2].replace('\'', ''),
            'address': parsedLine[4],
            'lat': null,
            'lng': null
          }

        turfs.push(voter)
      }).on('close', () => {
        let promisedTurfs = []

        const { turfs } = referenceJson,
          division = Math.ceil(turfs.length / numCPUs)

        while (turfs.length > 0) {
          promisedTurfs.push(
            axios({
              method: 'post',
              url: 'http://localhost:3002/api/multiThread',
              data: { turfs: turfs.splice(0, division) }
            })
          );
        }

        Promise.all(promisedTurfs).then((results) => {
          res.sendStatus(200)
        })
      })
    } catch (err) {
      console.log(err)
      res.sendStatus(500)
    }
  })