ktilcu

// Use the result of one promise to call another  and then that result and the first to call a third
const join = (fn, ...params) => Promise.all(params).then(ps => fn.apply(null, ps));

const makeRequest = () => {
  const p1 = promise1()
  const p2 = p1.then(promise2)
  return join(promise3, p1, p2)
}

ktilcu

const join = (fn, ...params) =>
  Promise
    .all(params)
    .then(ps => fn.apply(null, ps));

ktilcu

const Promise = require('bluebird')

const makeRequest = () => {
  const p1 = promise1()
  const p2 = p1.then(promise2)
  return Promise
    .join(p1,p2)
    .then(promise3)
}

ktilcu

const getAvatars = async (userId) => {
  const user = await getUser(userId);
  const avatar = await user.avatar();
  const friends = await user.friends();
  const avatars = [avatar];
  
  for (let friend of friends) {
    avatars.push(await friend.avatar());
  }
  

ktilcu

const getAvatars = async (userId) => {
  const user = await getUser(userId);
  const [avatar, friends] = await Promise.all([user.avatar(), user.friends()])
  const avatars = [avatar];
  
  for (let friend of friends) {
    avatars.push(await friend.avatar());
  }
  
  return avatars;

ktilcu

const getAvatars = async (userId) => {
  const user = await getUser(userId);
  const [avatar, friends] = await Promise.all([user.avatar(), user.friends()])
  const avatars = [avatar];
  
  return avatars.concat(
    await Promise.all(
      friends.map(friend => friend.avatar())
    )
  );

ktilcu

/** Promise Utility Functions **/
// Left to right function composition
const pipe = ([...asyncFns]) => input =>
  asyncFns.reduce((a, f) => a.then(f), Promise.resolve(input));

// One input passed to many processors simultaneously
const fan = ([...fns]) => value => Promise.all(fns.map(fn => fn(value)));

// Map a list with an async function and wait for all promises to resolve
const map = fn => list => Promise.all(list.map(fn));

ktilcu

const get = key => obj => obj[key];
const flatten = list => list.reduce((a, b) => a.concat(b), []);

//https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Using_promises
function queryAPI(region, realm, character) {
  if (region == null && realm == null && character == null) {
    return; // new Error or whatever
  }
  return blizzard.wow
    .character(['profile', 'items', 'talents', 'progression'], {

ktilcu

var friends =  await people.map(person => await person.getFriends());

ktilcu

/** Utility Functions **/
// Calls a method on an object
const call = method => value => value[method]();

/** Business Logic **/
const getUserAndFriendsAvatars = async user => {
  // get user
  const user = getUser(user);
  // get users friends
  const friends = user.then(call('friends'));