i have an issue accessing env variables in NodeJS - node.js

Question

Well, i have 3 types of environments (i.e development,test,production) am using nodejs with express. My problem is this my either development and production scripts don't run because they can't access .env variables i have searched online but i can't find something helpful. This is what i did i created .env file and put my variables in. i tried using export command i.e export key=value. please help
I created a .env file and added either of development database url and production database url, but when i run either of environment it doesn't work. i also tried using export command export key=value. but it works for a while and then it fails again.
//my config
require('dotenv').config();
module.exports ={
development :{
use_env_variable: process.env.DEVELOPMENT_URL,
dialect: 'postgres'
},
production :{
use_env_variable:process.env.PRODUCTION_URL,
dialect: 'postgres',
}
}
//my package.json scripts
{
"name": "report_deck",
"version": "1.0.0",
"description": "",
"main": "index.js",
"scripts": {
"start": "export NODE_ENV=production && sequelize db:migrate && node ./build/index.js",
"dev": "nodemon --exec babel-node ./api/index.js",
"test": "export NODE_ENV=test && sequelize db:migrate:undo:all && sequelize db:migrate && nyc --require #babel/register mocha ./api/test/test.js --timeout 20000 --exit",
"build": "rm -rf ./build && babel -d ./build ./api -s",
"generate-lcov": "nyc report --reporter=text-lcov > lcov.info",
"coveralls-coverage": "coveralls < lcov.info",
"codeclimate-coverage": "codeclimate-test-reporter < lcov.info",
"coverage": "nyc npm test && npm run generate-lcov && npm run coveralls-coverage && npm run codeclimate-coverage"
},
}
//.env
DEVELOPMENT_URL=postgres://example1:pass#example:5432/dbname
PRODUCTION_URL=postgres://example2:pass#example:5432/dbname
//my index.js
import express from 'express';
import bodyParser from 'body-parser';
import classRoutes from './server/routes/classRouter';
// all routes
import cors from 'cors';
const app = express();
app.use(bodyParser.json());
app.use(cors());
//use all routes
app.use(bodyParser.urlencoded({ extended: false }));
const port = process.env.PORT || 8003;
app.get('*', (req, res) => res.status(200).send({
message: "Entrance"
}));
app.listen(port, () => {
console.log("Entrance done, We are running at port " + port);
});
export default app;
Expectations:
It should log "entrance done we are running on port 8003" for (npm run dev)
It should log "entrance done we are running on port 5000" for(heroku local web)
Actual:
throw new TypeError('Parameter "url" must be a string, not ' + typeof url);

Answer 1

You should add -r dotenv/config to your starting script to preload dotenv =>
"start": "export NODE_ENV=production && sequelize db:migrate && node -r dotenv/config ./build/index.js",
Check docs