Avoid the "JavaScript heap out of memory" : Example of how to process huge CSV files using Streams in Nodejs.

process_csv_using_stream.js

#!/usr/bin/env node
const fs = require('fs')
const path = require('path')
const moment = require('moment')
const csv = require('fast-csv')
const highland = require('highland')

const writeableStream = fs.createWriteStream(path.join(__dirname, 'input.csv'))
const csvStream = csv.fromPath(path.join(__dirname, 'output.csv'), { headers: true, trim: true, objectMode: true })
const outputStream = csv.createWriteStream({ headers: true })

highland(csvStream).map(entry => {
  const athenaDate = moment(entry.date, 'DD/MM/YY').format('YYYY-MM-DD')
  return {
    keycode: entry.keycode,
    date: athenaDate,
    qty: entry.qty
  }
}).pipe(outputStream).pipe(writeableStream)