Async/await example.

async.js

/*
 * To run:
 *   npm install -g babel
 *
 *   babel-node --stage 0 this-script.js
 */

import fs from 'fs'

const mkDir = makePromisey(::fs.mkdir)

async function mkDirs(dirSegments) {
  let path = '.'
  for (let dirSegment of dirSegments) {
    path = path + '/' + dirSegment
    await mkDir(path)
  }
}

mkDirs(['a', 'b', 'c']).then(() => console.log('all done!'), e => console.log(`wtf: ${e}`))

function makePromisey(callbackyFunc) {
  return function(...args) {
    return new Promise((ok, notOk) => {
      callbackyFunc(...args, (err, ...vals) => {
        if (err) notOk(err)
        else ok(...vals)
      })
    })
  }
}