Data Archive

Node.js

Node.js is a JavaScript runtime environment that executes JavaScript outside the browser. It allows JavaScript to be used for server-side and general-purpose programming.

Core idea

Node.js embeds the V8 JavaScript engine (the same engine used by Chrome) and combines it with a set of system-level APIs. This makes it possible to run JavaScript files directly on an operating system:

node app.js

Key architectural characteristics

  1. Event-driven, non-blocking I/O Node.js uses an asynchronous execution model built around an event loop. I/O operations (network, filesystem) are handled without blocking the main thread, which is well-suited to high-concurrency workloads.

  2. Single-threaded execution model JavaScript code runs on a single main thread. Concurrency is achieved through asynchronous callbacks, promises, and an internal thread pool for certain operations.

  3. Standard library for system access Node.js exposes APIs for:

    • HTTP servers
    • File system access
    • Process and environment management
    • Networking

Practical use cases

  • Web APIs and backend services
  • Data pipelines and automation scripts
  • CLI tools and build systems
  • Real-time systems (e.g. WebSockets)

Relationship to npm

  • Node.js is the runtime that executes JavaScript.
  • npm is the package manager that installs libraries used by Node.js programs.
  • Together, they form the core tooling for server-side JavaScript.

Conceptual comparison

  • Browser JavaScript: sandboxed, DOM-focused, no direct file or network socket access.
  • Node.js JavaScript: system-level access, long-running processes, server execution.

If useful, I can map Node.js concepts to Python equivalents (e.g. Node.js vs CPython + asyncio) or explain the event loop in terms of task queues and microtasks.

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