stream.js

const xlsx = require('xlsx')
const { Writable, Transform } = require('stream')

const fs = require('fs')
const path = require('path')

console.log('início')


const workbook = xlsx.readFile('data-600.xlsx', { sheetStubs: true })
const sheet_name_list = workbook.SheetNames


const readableStreamFile = xlsx.stream.to_json(workbook.Sheets[sheet_name_list[0]], { raw: false })

const transformToString = new Transform({
  writableObjectMode: true,
  transform(chunk, encoding, callback) {
    callback(null, JSON.stringify(chunk))
  }
})


const writableStreamFile = new Writable({
  write(chunk, encoding, next) {
    const stringifyer = chunk.toString()
    const rowData = JSON.parse(stringifyer)
    fs.appendFileSync(path.resolve('data.log'), JSON.stringify(rowData) + '\n')
    next()
  },
})


console.log('Iniciou', Date())


readableStreamFile
  .pipe(transformToString)
  .pipe(writableStreamFile)
  .on('close', () => console.log('Finalizou', Date()))