só pra mim não esquecer como funciona essa merda.

stubs_events.js

var EventEmitter = require('events').EventEmitter,
    fs = require('fs'),
    util = require('util')

var Event = new EventEmitter(),
    readStream =  fs.createReadStream(__dirname+'./filename.txt','utf8'),
    writeStream = fs.createWriteStream(__dirname+'./filename_new.txt', {flags:'w'}),

    tmp_txt = [],
    v = {
      x: undefined,
      y: undefined
    }

readStream
  .on('close', function () {
    var ttxt = tmp_txt
    for (var i; 0 < ttxt.length; i++) {
      v.x = ttxt[i].z
      v.y = ttxt[i].w
    }
    console.log(util.format('Close %s file', this.path.split('/').pop()))
  })

  .on('data', function (d_txt) {
    tmp_txt += d_txt
    Event.emit('close')
  })