How to use the php:hmac_hash() function in javascript with nodejs package crypto

Im Trying to setup a Webhook in Javascript and have to validate a Header value with my secret

In php it works but in javascript doesn't works (sha256 missmatch)

The PHP Code is following:

$secret = "SUPERSECRETKEY";
//sig header
$headers = getallheaders();
foreach ($headers as $key => $value) {
    if (strtolower($key) === 'sig') {
        $sig = $value;
    }
}

//get the body
$body = file_get_contents('php://input');

//verify the signature

$hash = "sha256=".hash_hmac('sha256', $body, $secret);
if ($hash === $sig) {
    http_response_code(200);
} else {
    http_response_code(401);
}

and my javascript code is the following:

    var secret = "SUPERSECRETKEY";
    var sig = req.headers['sig'];
    var body = JSON.stringify(req.body);
    var hash = "sha256="+ crypto.createHmac('sha256', secret).update(body).digest('hex');
    console.log(sig)
    console.log(hash)
    if (hash === sig) {
        res.status(200).send("OK");
    } else {
        res.status(401).send("Unauthorized");
    }

Solution:

I have added to the app.js(express) following:

app.use(bodyParser.json({
    limit: '50mb',
    extended: true,
    verify: (req, res, buf, encoding) => {
        if (buf && buf.length) {
          req.rawBody = buf.toString(encoding || 'utf8');
        }
    },
}));