How to compute bandyer signature in Webhook Methods

BandyerSignature.js

const crypto = require('crypto');

const data = {
    event: "on_message_sent",
    "event_version": "0.1",
    "namespace": "chat",
    "data": "{}"
}
const secret = 'ak_fake_123456789';
const timestamp = '1554297654628';

const bandyerSignature = crypto.createHmac('sha256', secret).update(`${timestamp}.${data}`).digest('hex'));