Adding 'type': 'module' to the package.json enables ES 6 modules.
When you have 'type': 'module' in the package.json file, your source code should use import syntax. When you do not have, you should use require syntax.
Create a .env file and add the following code:
PORT=8000
DBURI=mongodb+srv://arnabmunshi:<password>@nodejs.1vdau.mongodb.net/<dbname>?retryWrites=true&w=majority