How to use the passport.authorize function in passport

state: 'success',
                data: req.user.access_token
            });
        } else {
            res.render('extenral_account_oauth', { 
                state: 'failure', 
                data: {
                    message: "Google+ authentication failed :("
                }
            });
        }
    });

    // connect to current session
    router.get('/auth/connect/google',
            passport.authorize('google', {
                scope : 'email'
            })
    );

    // disconnect from current session
    router.get('/auth/disconnect/google',
            function (req, res) {
                console.log('disconnect google');
                if (!req.user) {
                    res.send(401, { reason: 'not-authenticated' });
                } else {
                    var user = req.user;
                    user.google = undefined;
                    console.log('google info: ' + req.user.google);
                    user.save(function (err) {
                        if (err) {

router.get('/auth/github/callback', passport.authenticate('github', { failureRedirect: `${CLIENT_URL}/login` }), ((req, res) => {
  // successfull authentication from github
  res.redirect(`${CLIENT_URL}/verify_account`);
}));

// TWITTER
passport.use(new TwitterStrategy({
  consumerKey: process.env.TWITTER_KEY,
  consumerSecret: process.env.TWITTER_SECRET,
  callbackURL: `${SERVER_URL}/connect/twitter/callback`
}, (token, tokenSecret, profile, done) => {
  return done(null, profile)
}));

router.get('/connect/twitter', isAuthenticated, passport.authorize('twitter'));

router.get('/connect/twitter/callback',
  passport.authorize('twitter', { failureRedirect: `${CLIENT_URL}/dashboard/preferences` }), ((req, res) => {
    const { user, account } = req;

    User.findOne({ githubId: user.githubId }, (err, updatedUser) => {
      if (!err) {
        updatedUser.social.twitter = account.username;
        updatedUser.save();
        res.redirect(`${CLIENT_URL}/dashboard/preferences`);
        console.log('updated user with twitter handle');
      } else {
        console.log(err);
      }
    });
}));

});
}));

// LinkedIn
passport.use(new LinkedInStrategy({
  consumerKey: process.env.LINKEDIN_KEY,
  consumerSecret: process.env.LINKEDIN_SECRET,
  callbackURL: `${SERVER_URL}/connect/linkedin/callback`
}, (token, tokenSecret, profile, done) => {
  return done(null, profile)
}));

router.get('/connect/linkedin', isAuthenticated, passport.authorize('linkedin'));

router.get('/connect/linkedin/callback',
  passport.authorize('linkedin', { failureRedirect: `${CLIENT_URL}/dashboard/preferences` }), ((req, res) => {

    User.findOne({ githubId: req.user.githubId }, (err, updatedUser) => {
      if (!err) {
        updatedUser.social.linkedin = req.account.displayName;
        updatedUser.save();
        res.redirect(`${CLIENT_URL}/dashboard/preferences`);
        console.log('updated user with linkedin handle');
      } else {
        res.staus(500).send(err.message);
      }
    });
}));

// logout user & redirect to home page
router.get('/logout', function(req, res){
  req.logout();

router.get('/login/linkedin', passport.authenticate('linkedin', {
  state: auth.state,
  session: false,
}));

router.get(`/login${auth.linkedin.callbackURL}`, passport.authenticate('linkedin', {
  failureRedirect: '/login',
  session: false,
}), (req, res) => {
  const expiresIn = 60 * 60 * 24 * 180; // 180 days
  const token = jwt.sign(req.user, auth.jwt.secret, { expiresIn });
  res.cookie('id_token', token, { maxAge: 1000 * expiresIn, httpOnly: true });
  res.redirect('/login?callback=true');
});

router.get('/link/linkedin', passport.authorize('linkedin-link', {
  state: auth.state,
  session: false,
}));

router.get(`/link${auth.linkedin.callbackURL}`, passport.authorize('linkedin-link', {
  session: false,
}), (req, res) => {
  res.redirect('/profile');
});

router.get('/reload/linkedin', passport.authorize('linkedin-reload', {
  state: auth.state,
  session: false,
}));

router.get(`/reload${auth.linkedin.callbackURL}`, passport.authorize('linkedin-reload', {

state: auth.state,
  session: false,
}));

router.get(`/link${auth.linkedin.callbackURL}`, passport.authorize('linkedin-link', {
  session: false,
}), (req, res) => {
  res.redirect('/profile');
});

router.get('/reload/linkedin', passport.authorize('linkedin-reload', {
  state: auth.state,
  session: false,
}));

router.get(`/reload${auth.linkedin.callbackURL}`, passport.authorize('linkedin-reload', {
  session: false,
}), (req, res) => {
  res.redirect('/profile');
});

router.get('/login/google', passport.authenticate('google', {
  state: auth.state,
  scope: ['profile', 'email'],
  session: false,
}));

router.get(`/login${auth.google.callbackURL}`, passport.authenticate('google', {
  failureRedirect: '/login',
  session: false,
}), (req, res) => {
  const expiresIn = 60 * 60 * 24 * 180; // 180 days

res.cookie('id_token', token, { maxAge: 1000 * expiresIn, httpOnly: true });
  res.redirect('/login?callback=true');
});

router.get('/link/facebook', passport.authorize('facebook-link', {
  scope: ['email', 'user_birthday'],
  session: false,
}));

router.get(`/link${auth.facebook.callbackURL}`, passport.authorize('facebook-link', {
  session: false,
}), (req, res) => {
  res.redirect('/profile');
});

router.get('/reload/facebook', passport.authorize('facebook-reload', {
  scope: ['email', 'user_birthday'],
  session: false,
}));

router.get(`/reload${auth.facebook.callbackURL}`, passport.authorize('facebook-reload', {
  session: false,
}), (req, res) => {
  res.redirect('/profile');
});

router.get('/login/linkedin', passport.authenticate('linkedin', {
  state: auth.state,
  session: false,
}));

router.get(`/login${auth.linkedin.callbackURL}`, passport.authenticate('linkedin', {

req.flash('success', { msg: 'Tweet has been posted.' });
      res.redirect('/api/twitter');
    });
  });

  /**
   * OAuth routes for API examples that require authorization.
   */

  app.get('/auth/foursquare', passport.authorize('foursquare'));
  app.get('/auth/foursquare/callback', passport.authorize('foursquare', { failureRedirect: '/api' }), function (req, res) {
    res.redirect('/api/foursquare');
  });

  app.get('/auth/tumblr', passport.authorize('tumblr'));
  app.get('/auth/tumblr/callback', passport.authorize('tumblr', { failureRedirect: '/api' }), function (req, res) {
    res.redirect('/api/tumblr');
  });

};