CSVparser.js

var fs = require('fs');
var util = require('util');
var Stream = require('stream');

var file = fs.createReadStream('file.csv');
var parser = new CSV();

// values will be emitted
parser.on('value', function (value) {
  console.log(value);
});

file.pipe(parser);

function CSV() {
  Stream.call(this);
  this.buffer = '';
  this.writable = true;
}
util.inherits(CSV, Stream);

CSV.prototype.write = function (chunk) {
  var res = (this.buffer + chunk.toString()).split(',');
  
  // pull out the last data
  this.buffer = res.pop();

  res.forEach(this.emit.bind(this, 'value'));
};

CSV.prototype.end = function (chunk) {
  this.write(chunk);
  this.emit('value', this.buffer);
};