How to read .env file variables in Nodejs within Azure function

I have the following code which works fine locally, but when I deploy to an Azure function it fails to read in the contents of the .env file at runtime, when debugging each of the config items is "undefined". .Env file is deployed to Azure with correct entries and the function executes correctly when I hard code the config variables to test. I assume I need to do something differently to get this to work on Azure?

const sql = require('mssql')
require('dotenv').config();

const dbConfig = {
    server: process.env.databaseServer,
    database: process.env.databaseName,
    user: process.env.databaseUser,
    password: process.env.databasePassword,
    port: 1433,
    options: {
        encrypt: true,
        "enableArithAbort": true
    }
};