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 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.
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.
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.
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.
Server and client
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.
- Does the profile of the person or company who developed it look trustworthy?
- 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.
- Are there contributors who have co-developed or improved part of the module?