How Does Node js Works?

Node.js: What It Is?

Modern development techniques also depend on Node.js, which is a server platform based on the JavaScript Engine of Google Chrome (V8 Engine). Ryan Dahl created Node.js in 2009 and the most recent version is v0.10.36. Node.js is a JavaScript runtime that enables developers to build fast, scalable applications with ease.

It is a platform built on JavaScript of Chrome with runtime for creating rapid and scalable applications. Node.js is a non-blocking Input and output framework, an event-driven, that makes it quick and powerful for data-intensive real-time apps that run across distributed devices.

Node.js is a runtime environment for server-side and network programming that runs on Linux, OS X, Microsoft Windows, and other platforms. Node.js programs are written in JavaScript and maybe run within the Node.js runtime on Mac, Windows, or Linux.

Node.js also has a large collection of JavaScript modules that eases the creation of web apps using Node.js considerably.

Features Of Node.js

Node.js has a number of features that distinguish it as the first choice for software architects.

• Very Fast − Node.js, which is built on the V8 JavaScript Engine of Google Chrome, has a fast code execution because of the Node.js library.
• No Buffering − Node.js source code never buffers data, and applications created with Node.js do not buffer any data either. These apps just emit the information in parts.
• Asynchronous and Event-Driven − All Node.js library APIs are non-blocking, which means they don’t wait for an API to provide data. It essentially implies that a Node.js-based server never has to wait for an API to finish executing. After calling the next API, the server moves on to the following one, and there is a notification system in place for Node.js Events that allows the server to receive a response from the previous API call.
• Single-Threaded but Highly Scalable − Node.js utilizes a single-threaded approach with event looping. The event mechanism allows the server to deliver responses in a non-blocking manner and makes it extremely scalable rather than traditional servers, which create limited threads to handle requests. Node.js employs a single-threaded implementation, which allows it to service far more requests than traditional servers such as Apache HTTP Server.

How Does Node.js Work

Node.js communicates with the client through the requesting node. Node.js runs all I/O operations or requests using threads. Thread is a method of organizing code on a server so that it may perform multiple functions at once. To run I/O tasks or queries, node.js uses the idea of threads. A thread is a set of instructions for performing tasks on the server. It’s important to note that the server and client communicate using different protocols. It runs parallel to provide information to many users. Node.js is a single-threaded event loop language. With a single thread, it can handle multiple requests without blocking one of them.

Node.js basically operates on two concept

•  Non-blocking Input/Output
•  Asynchronous

Non-Blocking Input/Output

Non-blocking input/output (I/O) refers to working with multiple tasks without blocking the thread for a single task. I/O, in essence, deals with external systems such as files and databases. Because a single thread cannot handle the CPU workload, node.js is not utilized for calculation or video processing work that requires significant amounts of calculation speed.

Asynchronous

A callback function is being executed asynchronously. After receiving the response from another server or database, the node.js script will call a callback function. Because of its event-driven design, node.js employs callback functions and they are triggered as soon as some work is completed. The single thread, instead of responding to the request, routes it to another system that resolves the issue and is ready for a new request.

The system’s responsibility for the request is handled by the node.js platform via the concept of Libuv. Node.js is an open-source software library implemented in C++. It has a significant concentration on asynchronously and I/O, allowing nodes to access the underlying computer operating system, file system, and network.

Two essential features of node.js are implemented in Libuv:

Event loop: The event loop is a single thread that handles simple operations like calling callbacks and network I/O. The code is not in the callback function when the program initializes all of the top-level code. All of the code in callback functions will be executed in the event loop. The event loop is at the core of node.js. When we start a node application, the event loop immediately begins to execute. The majority of the processing happens in the event loop.

Thread pool: Node.js contains a thread pool even if it is single-threaded internally. A separate thread is used to accept non-blocking requests, while accepting blocking requests checks for available threads in a thread pool, assigns a thread to the client’s request, which is then processed and sent back to the event loop and responds by sending data to the specific client.

How Does Node.js Work Behind The Scene?

The Google V8 Engine is used in Node.js, which means that with the help of Node.js, we may execute JavaScript outside of the browser. Other facts about Node.js that you may or may not be aware of include its single-threaded design, event-driven architecture, and I/O model non-blocking implementation.

Node.js Architecture: It is based on the Chrome V8 engine, which is written in Libuv and  C++, a multi-platform C language library that supports event loops and thread loops with asynchronous Input and output based events. Don’t worry, it’ll be covered later on. Even though Node.js is written in C or C++ using the V8 engine and Libuv, it may still be used in pure JavaScript.

Node.js Application: Now that we’ve discussed the Node.js architecture, it’s time to look at how a Node.js application works and what makes it tick, which includes the notion of Node.js being single-threaded and its non-blocking nature. So, first and foremost, what do you mean by a thread?

A thread, in simple language, is a sequence of programming commands that may be run independently in the processor of a computer. Every process we want to execute has its own thread to execute the coding instructions, and each process can have many threads.

However, the important thing to remember is that Node.js applications only run on a single thread, which means that whether it is used by 5 users or 50 million users, it will only operate on a single thread and thus make the Node.js application blockable (which implies that a single line of code can block the entire app since a single thread is being utilized).