gistfile1.js

'use strict';

var fs = require('fs');

var csv = 'Header\r\n';
for (var i = 1; i <= 1000000; i++) {
  csv = csv + '"' + zeroPadding(i, 36) + '"';
  if (i % 100 === 0) {
    csv = csv + '\r\n';
  } else {
    csv = csv + ',';
  }
}
fs.writeFile('xxx.csv', csv, function(err) {
  if (err) {
    console.log(err);
    return;
  }
  console.log('complete');
})

function zeroPadding(number, length){
  return (Array(length).join('0') + number).slice(-length);
}