Example use of ES6 generator with 'co' and 'thunkify' modules to read four files in in parallel.

co-generator-ex1.js

#!/usr/bin/env node --harmony-generators

var fs = require('fs')
  , thunkify = require('thunkify')
  , co = require('co')
  , readFile = thunkify(fs.readFile)
  , fns = ["file0.txt", "file1.txt"
          , "file2.txt", "file3.txt"]

co(function*(){
  var contents, thunks
  thunks = fns.map(function(fn){
    return readFile(fn)
  })
  contents = (yield thunks).join('')
  console.log(contents)
})()