How node js works behind the scenes?

Node.js is a runtime environment that allows developers to execute JavaScript code on the server-side. It is built on the V8 JavaScript runtime engine, which was originally developed by Google for the Chrome browser. Here's an overview of how Node.js works behind the scenes:

1. V8 JavaScript Engine:Node.js utilizes the V8 JavaScript engine to execute JavaScript code. V8 compiles JavaScript code into machine code for faster execution.
2. Event-Driven and Non-Blocking I/O:One of the key features of Node.js is its event-driven, non-blocking I/O model. This means that the server doesn't wait for I/O operations (such as file or network requests) to complete before moving on to the next task. Instead, it registers callbacks, and when an I/O operation is finished, the corresponding callback is executed.
3. Event Loop:The event loop is at the core of Node.js. It constantly checks the message queue for events and executes the associated callback functions. This allows Node.js to handle multiple requests simultaneously without the need for multi-threading.
4. Single-Threaded Event Loop:While Node.js is single-threaded, it can handle a large number of concurrent connections because of its asynchronous, event-driven architecture. The event loop efficiently manages tasks, and I/O operations are delegated to the system kernel or external processes.
5. Libuv Library:Node.js relies on the Libuv library to handle the event loop and provide asynchronous I/O operations. Libuv abstracts the differences in the I/O operations across different operating systems.
6. Modules and npm:Node.js follows the CommonJS module system, allowing developers to organize code into modular components. The npm (Node Package Manager) ecosystem provides a vast collection of open-source libraries and packages that can be easily integrated into Node.js applications.
7. Concurrency Model:Node.js supports concurrency through an event-driven model, allowing it to handle many connections simultaneously. This is particularly well-suited for applications that require real-time features, such as chat applications or streaming services.
8. HTTP Module:Node.js includes an HTTP module that enables the creation of web servers. Developers can easily create server applications by using this module.
9. Buffers:Node.js introduces the concept of buffers to handle binary data efficiently. Buffers are used for reading or manipulating streams of binary data, which is common in networking and file systems.
10. Caching:Node.js caches required modules in memory. When a module is first loaded, it is cached, and subsequent requests for the same module are served from the cache. This helps in improving performance by reducing the need to reload modules from disk.

Understanding these underlying mechanisms helps developers leverage the strengths of Node.js for building scalable, high-performance applications. It is particularly effective for applications that require handling a large number of concurrent connections with low latency.