How to append new row in exist csv file in nodejs json2csv?

Question

I want to add new row in exist csv file? if csv file exist, then i don't want to add column header and just want to add new row after exist row in the file.

Here is code which I'm trying:

var fields = ['total', 'results[0].name.val'];
var fieldNames = ['Total', 'Name'];

var opts1 = {
  data: data,
  fields: fields,
  fieldNames: fieldNames,
  newLine: '\r\n'

};

var opts2 = {
  newLine: '\r\n',
  data: data,
  fields: fields,
  fieldNames: fieldNames,
  hasCSVColumnTitle: false,

};

fs.stat('file.csv', function (err, stat) {
  if (err == null) {
    console.log('File exists');
    var csv = json2csv(opts2);
    fs.appendFile('file.csv', csv, function (err) {
      if (err) throw err;
      console.log('The "data to append" was appended to file!');
    });
  } else if (err.code == 'ENOENT') {
    // file does not exist
    var csv = json2csv(opts1);
    fs.writeFile('file.csv', csv, function (err) {
      if (err) throw err;
      console.log('file saved');
    });
  } else {
    console.log('Some other error: ', err.code);
  }
});

Answer 1

The following code will do what you asked:

1. When run the first time- will write the headers
2. Each run after that - will append json the data to the csv file

var fs = require('fs');
var json2csv = require('json2csv');
var newLine = '\r\n';

var fields = ['Total', 'Name'];

var appendThis = [
  {
    Total: '100',
    Name: 'myName1',
  },
  {
    Total: '200',
    Name: 'myName2',
  },
];

var toCsv = {
  data: appendThis,
  fields: fields,
  header: false,
};

fs.stat('file.csv', function (err, stat) {
  if (err == null) {
    console.log('File exists');

    //write the actual data and end with newline
    var csv = json2csv(toCsv) + newLine;

    fs.appendFile('file.csv', csv, function (err) {
      if (err) throw err;
      console.log('The "data to append" was appended to file!');
    });
  } else {
    //write the headers and newline
    console.log('New file, just writing headers');
    fields = fields + newLine;

    fs.writeFile('file.csv', fields, function (err) {
      if (err) throw err;
      console.log('file saved');
    });
  }
});