Function to validate if all of env keys are present in your .env file (use dotenv dependency for parse data).

envValidatorService.js

const dotenv = require('dotenv');
const fs = require('fs');
const path = require('path');
const envSampleFilename = ".env.example"; //Create your own .env.example at root with dummy data and commit this file.
const envSample = fs.readFileSync(path.join(process.cwd(), envSampleFilename)).toString();
const buf = Buffer.from(envSample)
const sampleConfig = dotenv.parse(buf); // will return an object
const envsToValidade = Object.keys(sampleConfig);

module.exports = {
    validateAll: () => {
        envsToValidade.map(key => {
            if (!process.env[key]) {
                console.error(`ENV KEY '${key}' NOT FOUND! Check your .env file.`);
                process.exit(1);
            }
        })
    }
}