What is Node.JS?
There are three modules, core modules, third-party modules, and local modules. Core modules are inbuilt, pre-installed modules of node.js and Core modules are referenced simply by name while local modules and third-party modules map into a file path. Third-party modules are modules registered in NPM (Node Package Manager) and installed using npm command. NPM by default dumps modules installed from NPM repository into node_modules local directory. And local modules are self-created modules.
NPM-Node Package Manager:
This is a pre-installed package manager, which involves downloading packages of various local modules, self-published by resolving dependencies, running tests, and installing npm command-line utilities. The main purpose of NPM is to make it easier for developers to access and install reusable components from public libraries and repositories. A full list of packaged modules can be found on the NPM website https://npmjs.org/ or accessed using the NPM CLI (Command Line Interpreter) tool that automatically gets installed with Node. The Node’s module ecosystem is open to all, and anyone can publish their own module to be listed in the NPM repository.
How Node.js works?
Earlier, web browsers use to spawn new threads for each request to handle the concurrency. While node.js can handle concurrency of several connections and requests through a single thread system. Thus, a node js developer can develop an application high in response and low on memory footprint.
Non-Blocking Event Loop Feature:
The conventional blocking type feature used to block subsequent requests send to the server when the server was performing an I/O cycle. Node.js uses an event-loop feature to allow request processing alongside the I/O cycle. It is a software pattern that facilitates non-blocking I/O combined with event-driven I/O, a scheme where a registered event callback function is invoked when some action happens in the program.
While earlier browsers used to create threads for every subsequent request during the server’s I/O operations. Node.js uses a single thread system for all the subsequent requests, non-blocking I/O process. Whenever a Node application needs to perform operations, it sends an asynchronous task to the event loop, registers a callback function, and then continues to handle other operations. The event loop keeps track of the asynchronous operation, executes the given callback and when it completes, returns its result to the application.
Asynchronous Programming Feature:
Asynchronous programming makes it possible to handle the requests by effectively utilizing the limited clock cycles and memory available to its single-threaded architecture. All the APIs(Application Programming Interface) exposed through node.js are asynchronous. Node integrates asynchronous programming in its architecture by means of asynchronous APIs with a callback function.
AJAX and Node.js:
According to Nodesource, there has been substantial growth in contributors to the development of applications using node.js. mNode.js registered a whopping 368,985,998 downloads up till the end of 2018 from 2014. In 2018 alone nearly 600 contributors contributed towards node.js project along with 230 unique core contributors in October 2018 alone. Among the companies that have implemented Node JS are Amazon, Netflix, eBay, Reddit, LinkedIn, Tumblr, and PayPal. Some of the reasons to choose Node JS are the “futuristic” features (Amazon) and because it reduces startup time (Netflix). The application area of Node JS includes IoT, crowdfunding, e-commerce, and payment processing. More than 85 countries and users with 45 different native languages use Node JS worldwide.
In AJAX, Clients always have to query the server community for new data that is available for application and the server cannot push data without being asked by the client, which leads to users, unable to see the real-time data.
Wrapping it Up: