In this post, we will explore and elaborate the architecture of Node.js and Node.js-based applications. We will also explore some of the design patterns that are implemented in Node.js. Node.js typically provides the capability of ensuring that we are able to provision a single-threaded event loop mechanism. Deviating from multi-threaded mechanism to single-threaded was a smart move made by Node.js. And the architecture of Node.js supports single-threaded mechanism.
The base level of the Node.js architecture contains certain libraries, like V8. V8 is Google Chrome’s super fast library, which provides native capability to Node.js so we can execute the threads faster. There are two different pools. One of them is the thread pool and the other is the event pool. The responsibility of the event pool is to build event queues and then process the events one at a time. The responsibility of the thread pool is to ensure that the requests are received and managed by a single thread and then pass them on to the event loop. The base level also includes the DNS, which is used to explore the domain, and there’s crypto, which is used to implement security. On top of the libraries, there are various node bindings.
The node bindings include socket and HTTP.
The node binding is typically used to facilitate communications with external systems. For example, if we want to communicate with HTTP servers, we can use HTTP binding. If we want to communicate with WebSocket that internally use sockets, we can use socket API. Similarly, for messaging NoSQL servers or any external systems, there will be node bindings that we can use to establish communication.
Now let’s explore a typical architecture of a Node.js-based application.
We know any application today will contain three important parts, server side, client side, and storage. Now, Node.js architecture also supports such architectural model where Node.js facilitates or implements the server side connection. There are various Google Chrome extensions for client side connection and also to help clients write or build applications locally, which can then be manipulated by node libraries. So where there’s WebSockets for real time interactive communication, then there’s notification to notify the server and the client.
Followed by local storage to ensure that the storage is shared between the client and the server. The final part of the architecture is the data storage for which we can use MongoDB, which is an efficient NoSQL database that can store data using JSON or a native format called PSON. This architecture is perfectly illustrated in this sample figure. So the data is being streamed from various channels like social media or through the browser extensions. Then Node.js takes the responsibility of managing the server side communication. And it negotiates with the database MongoDB to store and manage the data using Node.js libraries.
Design Patterns Implementation in Node.js
In order to ensure that Node.js provides efficient approach of building and managing applications, it has implemented various design patterns. We will explore these design patterns and elaborate their implementation in Node.js. The first pattern is the singleton, which is implemented for single-threaded mechanism. Observer pattern implemented and utilized by the event loops. And then the factory pattern is implemented in Node.js to help create objects. The fourth pattern, dependency injection pattern, is implemented to facilitate the principle of don’t call us, we will call you, so as to reduce the lookups.
Now, the middleware and pipeline pattern is implemented to provision intermediaries in Node.js-based applications and add value in terms of request processing. The final pattern, which is stream pattern, is implemented to help Node.js applications work with streams by writing and reading streams on any interface, be it files, networks, or ports. So by using Node.js, we will be able to build applications that are small, concise, and modular. Since Node.js internally uses object-oriented and event mechanism principles, it is considered to be one of the better choices for building applications.
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