How to add new column to csv file using node js

csv, node.js

Solution

Use csv-parser package instead of fast-csv, and json2csv for json to csv parsing.

What you want to do is to convert each row of the csv to json using csv-parser, add a new field into the resulting json object, do this for each row, put the result in an array, convert that array into csv with json2csv package.

Here is the code:

var csv = require('csv-parser');
var fs = require('fs');
var json2csv = require('json2csv');
var dataArray = [];

fs.createReadStream('your-original-csv-file.csv')
  .pipe(csv())
  .on('data', function (data) {
    data.newColumn = newColumnValue;
    dataArray.push(data);
  })
  .on('end', function(){
    var result = json2csv({ data: dataArray, fields: Object.keys(dataArray[0]) });
    fs.writeFileSync(fileName, result);
  });

fs.writeFileSync overrides the original file anyway, so you can also save into the original csv file.

Problem

I already tried this using node.js npm package fast-csv, but I don't get a solution, I can read csv file successfully, now I need to add a new column to my existing csv file. My questions: How to add new column to csv file? How to update csv? ``` var csv = require("fast-csv"); var fs = require('fs'); var stream = fs.createReadStream("file1.csv"); var service = 'https://maps.googleapis.com/maps/api/distancematrix/json?origins=53.78943,-0.9985&destinations=53.540867,-0.510699&mode=driving&language=en-US'; var source = []; var dest = []; var distance = require('google-distance'); distance.apiKey = '************'; var i = 1; csv .fromStream(stream, { headers: true }) .on("data", function(data) { //get source and distance array source = data.SourceLatLong; dest = data.DestBREPLatLong; //print source and destinatoon console.log(source); console.log(dest); distance.get({ // index: i, origin: source, destination: dest, units: 'imperial' }, function(err, map_data) { if (err) return console.log(err); //console.log(map_data); //console miles of aff console.log('source lat long ' + ':' + data.SourceLatLong + ' , ' + 'Dest lat long' + ':' + data.DestBREPLatLong + ',' + ' distance ' + ':' + map_data.distance + ' ' + i++); }); }) .on("end", function() { console.log("done"); }); ``` In the above program I use the filecsv file1.csv ,from i take two columns `SourceLatLong` and `DestLatLong` and I calculate distance in miles. Now I need to add new miles columns to my file .csv

Original source