SyntaxError: Unexpected identifier - express.js : <p>I have the the following server created with <code>express.js</code></p>

<pre><code>const express  = require('express')
const app      = express()
var bodyParser = require('body-parser');
var cors       = require('cors');

app.use(cors());
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));

app.use(function(req, res, next) {
   res.header("Access-Control-Allow-Origin", "*");
   res.header('Access-Control-Allow-Methods', 'DELETE, PUT');
   res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
   next();
});

app.post('/api/v1/login.json', function (req, res) {
  var user = login(req.body.email, req.body.password)

  if user !== null {
    res.status(200).json({token: "test_token"});
  } else {
    res.status(401).json({error: 'Niepoprawny email lub hasło.'});
  }
})

app.listen(3000, function () {
  console.log('server listening on port 3000')
})

const users = [
  {
    id: 1,
    email: 'test@user.com',
    password: 'password',
    access_token: 'test_user_access_token'
  },

  {
    id: 2,
    email: 'second@user.com',
    password: 'password',
    access_token: 'second_user_access_token'
  }
]

function login(email, password) {
  return users.find(x =&gt; x.email === email &amp;&amp; x.password === password);
}
</code></pre>

<p>When I try to run it, it returns following error:</p>

<pre><code>  if user !== null {
     ^^^^
SyntaxError: Unexpected identifier
</code></pre>

<p>How can I fix this?</p>
