How is external module connection implemented in Node.js environment?

In Node.js, external modules are connected using the require function (CommonJS) or import (ES Modules).

Example with CommonJS:

const express = require('express');
const app = express();

Example with ES Modules (if "type": "module" is specified in package.json):

import express from 'express';
const app = express();

Modules are installed via npm or yarn, for example:

npm install express

After installation, they can be imported in the code.