Medium, creating a facebook login, facebook directive v. basic

gistfile1.js

'use strict';

var app = angular.module('ctLoginsApp.facebook.directives', ['ngResource']);

app.directive('facebook', ['$window', '$compile', '$q', function($window, $compile, $q) {

  var link = function(scope,element,attrs) {

  function statusChangeCallback(response) {
    console.log('statusChangeCallback');
    console.log(response);

    if (response.status === 'connected') {

      testAPI();

    } else if (response.status === 'not_authorized') {

      document.getElementById('status').innerHTML = 'Please log ' +
        'into this app.';

    } else {

      document.getElementById('status').innerHTML = 'Please log ' +
        'into Facebook.';

    }
  }

  function checkLoginState() {
    FB.getLoginStatus(function(response) {
      statusChangeCallback(response);
    });
  }

  window.fbAsyncInit = function() {
  FB.init({
    appId      : '{your-app-id}',
    cookie     : true,  // enable cookies to allow the server to access 
                        // the session
    xfbml      : true,  // parse social plugins on this page
    version    : 'v2.1' // use version 2.1
  });

  FB.getLoginStatus(function(response) {
    statusChangeCallback(response);
  });

  };

  // Load the SDK asynchronously
  (function(d, s, id) {
    var js, fjs = d.getElementsByTagName(s)[0];
    if (d.getElementById(id)) return;
    js = d.createElement(s); js.id = id;
    js.src = "//connect.facebook.net/en_US/sdk.js";
    fjs.parentNode.insertBefore(js, fjs);
  }(document, 'script', 'facebook-jssdk'));

  function testAPI() {
    console.log('Welcome!  Fetching your information.... ');
    FB.api('/me', function(response) {
      console.log('Successful login for: ' + response.name);
      document.getElementById('status').innerHTML =
        'Thanks for logging in, ' + response.name + '!';
    });
  }

  };

  return {
    link: link,
    scope: {
      appId: '@'
    },
    template: '<div>Loading...</div>'
  };

}]);