Promise Example for Promise Talk

promise-example.js

const githubApi = 'https://api.github.com';
const githubEventUrl = githubApi + '/users/machuga/events';

fetchReposForLatestActivity('machuga').then(console.log);

function fetchReposForLatestActivity(user, fn) {
  return new Promise(function(resolve, reject) {
    request(githubEventsUrlFor(user))
    .then(getThreeEvents)
    .then(fetchRepos)
    .then(function(repos) {
      resolve(repos.map(getRepo));
    });
  });
}

function fetchRepos(events, fn) {
  return Promise.all(events.map(function(e) {
    return request(githubRepoUrlFor(e.repo.name));
  }));
}

function getRepo(repo) {
  return {
    author: repo.owner.login,
    avatar: repo.owner.avatar_url,
    name: repo.name,
    full_name: repo.full_name,
    url: repo.html_url,
    description: repo.description
  };
}

function getThreeEvents(events) {
  return events.slice(0, 3);
}

function githubEventsUrlFor(user) {
  return githubApi + '/users/'+user+'/events';
}

function githubRepoUrlFor(repo) {
  return githubApi + '/repos/'+repo;
}

function log(a) {
  console.log(a);
}

function request(url, fn) {
  return Promise.resolve($.getJSON(url).then(fn));
}