Modules (1/5)
Discuss different module system available to node js and difference between them?
    Node.js supports two primary module systems: CommonJS and ECMAScript Modules (ESM). Let’s break down each one and highlight their differences:
    CommonJS is the original module system for Node.js. It uses the require function to import modules and module.exports or exports to export them.
    Features:
    • Synchronous loading of modules. Blocks execution until the module is loaded.
    • Dynamic Analysis: Modules can be required inside functions or if blocks.
    • Each file is treated as a separate module.
    • Requires a bundler like Webpack on browsers
    • Does not support top-level await.
    • File extension: .cjs, js
    ECMAScript Modules (ESM) are the standardized module system for JavaScript, used in both browsers and Node.js. It uses import and export statements.
    Features:
    • Asynchronous loading of modules. Allows for better performance and parallelism.
    • Static analysis of imports and exports, Imports must typically be at the top level, allowing for 'tree-shaking' (removing unused code). which can improve performance and tooling.
    • Supports top-level await.
    • Supported by all modern browsers.
    • File extension: .mjs, js
    Key Differences:
    • Syntax: CommonJS uses require and module.exports, while ESM uses import and export.
    • Loading: CommonJS modules are loaded synchronously, whereas ESM modules are loaded asynchronously.
    • Scope: ESM supports block-scoped imports and exports, which can lead to better optimisation and tree-shaking.
    • Compatibility: CommonJS is more widely used in existing Node.js projects, but ESM is the standard for modern JavaScript development and is increasingly adopted.

    Both module systems have their own advantages and use cases. CommonJS is great for compatibility with existing Node.js code, while ESM is the future-proof choice for modern JavaScript development.