Error occurred (ECONNREFUSED) while trying to proxy request React/ Express (npm run start)

Question

Hello and hope you are well.

When running npm run start on my project, it is not working because it seems to build the files only once and not watch for it. So it is not compiling the FE part and only running server side.

package.json

"scripts": {
    "build": "node build.js",
    "start": "node index.js",
    "test": "jest",
    "lint": "eslint . --ext=js,jsx,mjs --max-warnings=0 --color || true",
    "lint:fix": "eslint . --ext=js,jsx,mjs --max-warnings=0 --color --fix || true"
},

bundle-server.js

const app = express();

app.use(require("./build.js"));

app.listen(8081, () => console.log("Ready to compile and serve bundle.js"));

index.js

    app.use(
        "/bundle.js",
        require("http-proxy-middleware")({
            target: "http://localhost:8081/"
        })
    );
} else {
    app.use("/bundle.js", (req, res) => res.sendFile(`${__dirname}/bundle.js`));
}

///////////-------///////////

if (require.main == module) {
    app.listen(process.env.PORT || 8080, () => console.log("Server Listening"));
}

there is as well a db.js

const db = spicedPg(
    process.env.DATABASE_URL ||
    "postgres:postgres:postgres@localhost:5432/contacts"

);

When running npm start or npm run start, the following error is shown:

Server Listening
[HPM] Error occurred while trying to proxy request /bundle.js from localhost:8080 to http://localhost:8081/ (ECONNREFUSED) (https://nodejs.org/api/errors.html#errors_common_system_errors)

I am not sure if this could be from the

const db = spicedPg(
   process.env.DATABASE_URL ||
   "postgres:postgres:postgres@localhost:5432/contacts"

as I am not passing the correct ref to call the database ? In addition, this is a production set up and not a dev one, so this could be the source too.

Where should I look in the code base to tackle this ECONNREFUSED ?

Please find the repo here

Thank you for taking the time