Node.js and Deno are two platforms for running JavaScript and TypeScript outside the browser, but they have several differences in design and architecture.

Node.js

• Release Date: Introduced in 2009, Node.js enables JavaScript execution on the server using Google's V8 engine.
• Key Features:
  • CommonJS Modules: Node.js uses the CommonJS module system, where modules are imported via require().
  • NPM (Node Package Manager): Node.js relies on NPM, a massive package repository that serves as the primary dependency management tool.
  • Asynchronous I/O Model: Node.js utilizes a non-blocking I/O model, making it highly efficient for handling network requests and a large number of connections.
  • Security: Node.js provides extensive access to the file system and network capabilities by default, which can be unsafe unless properly secured.
  • JavaScript Support: Initially, it only supported JavaScript. TypeScript support is available via external tools and compilation.

Deno

• Release Date: Launched in 2020 by Ryan Dahl (the creator of Node.js), who aimed to address some architectural issues of Node.js.
• Key Features:
  • ES Modules: Unlike Node.js, Deno uses the standard ECMAScript module system (ESM). Modules are imported using import syntax and can be sourced via URLs.
  • Security: Deno is more secure by default. Explicit permissions are required to access the file system, network, and other resources. For example, to read a file, you must run the command with the --allow-read flag.
  • TypeScript Support: Native TypeScript support is built-in, eliminating the need for additional tools or compilation.
  • Package Management: Deno does not use a centralized repository like NPM. Instead, modules are imported directly from URLs, such as GitHub or other sources.
  • Compatibility: Deno provides built-in APIs that align with standard Web APIs, making it more compatible with modern frontend development.

Key Differences:

1. Module System:

   • Node.js: Uses CommonJS with require().
   • Deno: Uses ECMAScript modules with import/export.

2. TypeScript Support:

   • Node.js: Supported via compilation or external tools.
   • Deno: Native TypeScript support without extra setup.

3. Security:

   • Node.js: Full access to system resources by default.
   • Deno: Secure by default–explicit permissions are required for access to resources (file system, network, etc.).

4. Package Management:

   • Node.js: Uses NPM for package management.
   • Deno: No centralized package manager; modules are imported via URLs.

5. Creation Date:

   • Node.js: Created by Ryan Dahl in 2009.
   • Deno: Created by the same Ryan Dahl in 2020.

When to Use What?

• Node.js: Ideal for developers already working within the NPM ecosystem or using numerous JavaScript libraries built on this platform.
• Deno: Best suited for developers who prioritize built-in TypeScript support, stronger default security, and adherence to modern JavaScript specifications.

Thus, Deno presents a more modern and secure alternative to Node.js, but Node.js remains the more mature and widely adopted option for production projects.