Transforming CSV data

csv-map.js

const fs = require("fs")
// The 3 following modules need to be installed
const csvStream = require("csv-stream") 
const csvWriteStream = require("csv-write-stream")
const through2Map = require("through2-map")

fs.createReadStream("in.csv")
  .pipe(csvStream.createStream({
    // will use the first line as a header containing the keys for the resulting objects
    delimiter: ";" // other options: https://www.npmjs.com/package/csv-stream
  }))
  .pipe(through2Map.obj(row => {
    // This function is called for each row in the CSV file
    // row is an object with a key for each column: row.column1, row.column2...
    // This function should return the transformed object.
    // e.g. 
    // return Object.assign(row, {
    //   column1: "value",
    //   column2: parseInt(row.column2) + 1
    // })
  }))
  .pipe(csvWriteStream({
    separator: ";" // other options: https://www.npmjs.com/package/csv-write-stream
  }))
  .pipe(fs.createWriteStream("out.csv"))