Node.js: what is it? Functions, application & basics

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Node.js: what is its essence? How does it work? What are the main features? Learn all you need to know about it here!

Node.js: top features and more

Node.js is a framework for the JavaScript scripting language. This is an open-source runtime environment. This allows JavaScript code to be executed outside a web browser. Just like JavaScript, Node.js is platform-independent. We discuss in detail here what advantages Node.js has in the creation of websites. As we know, there is an incredible number of applications built with Node.js, so further information will definitely be useful.

Understanding Node.js

JavaScript was developed to generate dynamic website content in the browser. If a person also wanted to generate dynamic content on the server, he still depended on choosing another language at the beginning. JavaScript was intended exclusively for programming on the part of the web browser. In 2009, Node.js was then launched by Ryan Dahl to close this gap.

Node.js acts on the server side and works event-based. What exactly do event-based mean? In the context of web development, an event is an action that can be responded to. You can distinguish events into categories, such as user-based events such as a mouse click, keyboard, or voice input. Another category would be the application-generated events, for example, when an HTTP call or file access has been completed. The program can react to these actions, i.e., one can carry out one or more subsequent actions with a mouse click.

The framework is now considered one of the best-known and most widely used JavaScript frameworks. Based on the V8 engine of Google Chrome, which is also used to run JavaScript, Node.js can be easily used with JavaScript.

Node.js in the application

Due to its event-based properties, Node.js is welcome in web server development. For a long time, servers were thread-based and not event-based. But what difference does it make? An example:

There is a long queue in a fast food restaurant. The person at the checkout orders their food and then stops in line until their order is ready. The checkout cannot process any other customers during this time. This would be the same as thread-based servers. An event-based server would work as follows: There is a long queue in our fast food restaurant again. The person at the checkout orders their food and then goes to another place to wait for their order. This allows the cash register to process the next customer. As soon as the first customer’s order is ready, he will be notified and can pick it up. We are well aware of this principle, and it also works efficiently in real life.

Attentive readers will now notice that event-based processes pose a risk of blockages. In our fast food example, this could happen, for example, through online orders, which makes the process of on-site customers stall a little.

With Node.js, it is possible to make sure that there are no blockages during these events. The entry and exit of the events must not be hindered; this is then called non-blocky I/O.

In addition, it is also possible to create software far outside of web development. This allows scripts to be created for the command line and desktop applications. As with any other all-rounder language, caution applies here as well because the pure possibility of wide-ranging use offers no guarantee of security or elegant solutions.


Let’s take a look at some of the main features of Node.js.

Asynchronous communication

This feature is also known as non-blocking I/O. Synchronous threads, which start a separate thread for each request and block the entire process, are to be avoided. In this way, Node.js helps the web server to stop starting individual threads. Instead, so-called single threads are started with Node.js. These are then processed one after the other in an endless loop.


The endless loop for processing single threads is realized by the Libuv component. By default, this library creates a thread pool. By default, up to four threads can be processed simultaneously. Libuv also sends requests to the operating system, which takes care of the timing of the threads. This allows actions to be carried out without waiting for a previous action.

Event stack

With the help of the event stack, actions are sorted and processed continuously. This is done according to the LIFO pattern: Last In, First Out. This event stack, also called an event loop waits for a function to be executed in the stack. At the same time, new functions are added to the stack.

Node.js core

The V8 engine, which is also executed in the browser, allows Node.js to be easily used with JavaScript. Unfortunately, the engine is extremely restrictive. For example, the file system cannot be accessed, or functions of the operating system cannot be used. This has security reasons, as websites should not be able to access the file system of visitors without being asked.

With the Node.js Core, which, like the engine, was also developed in C++, features are provided that master much more than the V8 engine. The functions are provided with wrappers that enable C++ implementations under JavaScript. This also includes methods with which HTTP requests and responses can be processed. Thus, the V8 engine is enriched with other functions important for backend languages.

Server and client

The tool is particularly popular for beginners. JavaScript alone is easily accessible and can be quickly learned by new web developers. With the introduction of Node.js, it is also possible to develop the backend in the same programming language and to draw on existing know-how.

Node Package Manager

Node.js has already installed a number of extremely useful modules during the initial installation. For example, the URL module, with which functions are added, simplifies working with URLs. To add more modules for your own individual purpose, there is the Node Package Manager (npm). It is also available during the initial installation. With an overwhelming number of more than 350,000 packages, there is no wish left out.

But how do you recognize a good npm module? It can be helpful to take a closer look at the GitHub repository.

  1. Does the profile of the person or company who developed it look trustworthy?
  2. How many stars did the project receive? The much-used modules will have a high number of stars. It becomes more difficult to check this for special and unique use cases. The more exotic the requirements, the less often such a module is called.
  3. Are there contributors who have co-developed or improved part of the module?


Node.js shines above all in combination with JavaScript. Being able to write both frontend and backend in the same language provides an easy entry point for many. With the help of the Package Manager, numerous packages can be used. Many modules have already been created by other developers and thus facilitate your own development. Thanks to event-based capabilities and asynchronous communication, developing dynamic web content is child’s play.

Also Read: The profession of a web developer: tasks, skills, career

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