passport-jwt middleware not being hit

I'm trying to create jwt auth with passport-jwt but I'm having a hard time figuring out why the callback is never triggered for the JwtStrategy (auth.passport.js):

app.js

const express       = require('express');
const bodyParser    = require('body-parser');
const mongoose      = require('mongoose');
const Auth          = require('./modules/auth/auth.main');
const User          = require('./modules/user/user.main');
const Foo           = require('./modules/foo/foo.main');
const config        = require('./config/database');
const AuthPassport  = require("./modules/auth/auth.passport")();

class App {

  // express : require('express')
  constructor () {
    this.express  = express();
    this.middleware();
    this.database();
    this.routes();
  }

  middleware () {
    //this.app.use(logger('dev'));
    this.express.use(bodyParser.json());
    this.express.use(bodyParser.urlencoded({ extended: false }));
    this.express.use(AuthPassport.initialize());
  }

  database () {
    mongoose.Promise = global.Promise; // use built-in Promise
    mongoose.connect(config.address);
  }

  routes () {
    this.express.use('/api/v1/auth' , Auth);
    this.express.use('/api/v1/users', User);
    this.express.use('/api/v1/foos', AuthPassport.authenticate(), Foo);
  }

}

module.exports = new App().express;

auth.passport.js

const passport    = require("passport");  
const JwtStrategy = require('passport-jwt').Strategy;  
const ExtractJwt  = require('passport-jwt').ExtractJwt;
const config      = require("../../config/config");
const UserModel   = require("../user/user.model");

// refer to: https://github.com/themikenicholson/passport-jwt
module.exports = () => {  
  var opts = {};
  opts.jwtFromRequest = ExtractJwt.fromAuthHeader();
  opts.secretOrKey = config.jwt.secret;

  passport.use(new JwtStrategy(opts, function(jwt_payload, done) {
    console.log("jwt_payload", jwt_payload); // not being triggered

    UserModel.findOne({_id: jwt_payload.sub}, function(err, user) {
        if (err) {
          return done(err, false);
        }
        if (user) {
          return done(null, user);
        } else {
          return done(null, false);
          // or you could create a new account
        }
    });
  }));

  return {
    initialize: function() {
      return passport.initialize();
    },
    authenticate: function() {
      return passport.authenticate("jwt", { session: false });
    }
  };

};

The console.log that I have inside the callback of the jwt strategy is not being triggered at all (see "// not being triggered" comment) when I send a request to the Foo route, and I'm getting "Unauthorized" every single time.

I'm guessing I'm doing something completely wrong but I can't figure it out.

via FPJ