Crear sesion usando facebook

lib.facebook.js

var fbGraph = require('fbgraph');
var FACEBOOK_APP_ID = process.env.FACEBOOK_APP_ID;
var FACEBOOK_APP_SECRET = process.env.FACEBOOK_APP_SECRET;

function validateTokenAndGetProfile(token, cb) {
  fbGraph.setAccessToken(token);  
  fbGraph.setAppSecret(FACEBOOK_APP_SECRET);
  fbGraph.get('/me?fields=id,email,name,gender,bio,picture.type(large)', function(err, result) {
    if (err) return cb(new Error(err.message));
    cb(null, result);
  });
}