NodeJS JWT token verification

I'm trying to verify a signed token and extract information from it using NodeJS.

I have a token named userToken in the browser right now, it has been saved after I logged in (I use auth0 to login by the way).

I tried to verify my token here manually : http://jwt.io , it works and gives me payload data without a problem. However, I can't do the same thing with NodeJS. How can I do it?

I read the docs but I couldn't get it. https://github.com/auth0/express-jwt

Here's my server.js

var http = require('http');
var express = require('express');
var cors = require('cors');
var app = express();
var jwt = require('express-jwt');
var dotenv = require('dotenv');

dotenv.load();

var authenticate = jwt({
    secret: new Buffer(process.env.AUTH0_CLIENT_SECRET, 'base64'),
    audience: process.env.AUTH0_CLIENT_ID
});


// view engine setup
var path = require('path');
app.set('views', path.join(__dirname, 'views'));
app.use(express.static(path.join(__dirname, 'public')));

app.set('view engine', 'jade');


app.configure(function () {

    // Request body parsing middleware should be above methodOverride
    app.use(express.bodyParser());
    app.use(express.urlencoded());
    app.use(express.json());
    app.use(cors());

    app.use(app.router);
});


app.get('/', function (req, res) {
    res.render('index');
});

app.get('/test', function(req,res) {
    // how do I check it?
});


var port = process.env.PORT || 3001;

http.createServer(app).listen(port, function (err) {
    console.log('listening in http://localhost:' + port);
});