seanstrom

// Part 2

getFile(path, function(err, message) {
  if(err) {
    console.error(err)
  } else {
    console.log(message)
  }
})

seanstrom

// Part 1

var fs = require('fs')
  , path = 'my_file.txt'
 
function getFile(path, callback) {
  fs.readFile(path, function(err, data) {
    if(err){
      return callback(err)
    }

seanstrom

function getTweetsPostsRepos(username) {
  var tweets = getTweets(username)
  var posts = getPosts(username)
  var repos = getRepos(username)
  
  return Promise.all([tweets, posts, repos])
}

var username = 'seanghagstrom'

seanstrom

function findLikesForPostsByUsername(username, callback) {
  var promise = new Promise(function(resolver, rejector) {
    findUserByUsername(username)
      .then(findPostsByUser)
      .then(findLikesByPosts)
      .then(function(likes) {
        var totalLikes = likes.reduce(function(x, y) { return x + y })
        resolver(totalLikes)
      })
      .catch(function(err) {

seanstrom

var http = require('special-http')
 
function getData(endpoint, callback) {
  var promise = new Promise(function(resolver, rejector) {
    if(cache[endpoint]) {
      return resolver(cache[endpoint])
    }
  
    http.get(endpoint).then(function(data) {
      resolver(data)

seanstrom

var http = require('special-http')
 
function getData(endpoint, callback) {
  if(cache[endpoint]) {
    return setTimeout(function() {
      callback(null, cache[endpoint])
    }, 0)
  }
  
  http.get(endpoint, function(err, data) {

seanstrom

var http = require('special-http')

function getData(endpoint, callback) {
  if(cache[endpoint]) {
    return callback(null, cache[endpoint])
  }
  
  http.get(endpoint, function(err, data) {
    if(err) {
      return callback(err)

seanstrom

function throwsError() {
  throw new Error('silly error')
} 

var endpoint = 'my/endpoint'
var dataPromise = getData(endpoint)
 
dataPromise
  .then(function(data) {
    return throwsError()

seanstrom

var fs = require('fs-promise')
  , path = 'my_file.txt'
 
var filePromise = fs.readFile(path)
 
filePromise.then(
  function(fileData) {
    console.log('done')
  },
  function(error) {

seanstrom

function getTweetsPostsRepos(username, mainCallback) {
  async.parallel([
    function(callback) {
      getTweets(username, callback)
    },
    function(callback) {
      getPosts(username, callback)
    },
    function(callback) {
      getRepos(username, callback)