Does DuplexPair Crack Down WebSockets? A Ninja Technique Unveiled in Node.js 22.6

The DuplexPair API in Node.js, introduced in version 22.6.0, offers a powerful mechanism for creating interconnected Duplex streams, enabling bidirectional communication within applications. But are you familiar with the concept of duplex stream, which remained in Nodejs for a long time before the DuplexPair concept was introduced in Aug 2024? Do you know if it is safe to use? Will it diminish WebSocket programming in Node.js? So all these led me to write this article to answer these burning questions by exploring the functionality, use cases, and differences between DuplexPair and WebSockets, highlighting their significance in modern Node.js development. Join me as we explore the new horizon of the DuplexPair API.

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Differences Between Buffer and Stream

Before diving into the main topic, I'd like to address a niche but important distinction. Do you know the differences between a stream and a buffer? Developers often use these terms interchangeably, but that’s fundamentally incorrect. So, before we go any further in this article, I want to take a moment to clarify this common misconception that I've observed among many developers I've worked with or interviewed.

A buffer is a chunk of memory allocated to store binary data. Once created, the size of a buffer cannot be changed. Buffers are used for handling raw binary data, such as files or network protocols.

On the other hand, a stream is an abstraction for working with streaming data. It allows data to be read from or written to a source in a continuous flow, rather than loading the entire data set into memory at once. In Nodejs, there are 4 types of Streams available as follows:

• Readable streams → This stream is used to create a stream of data for reading, for example: to read a large chunk of files.
• Writable streams?→ This stream is used to create a stream of data to write. For example: to write a large amount of data in a file.
• Transform streams →?This stream is used to create a readable and writable stream, but the data in the stream can be modified while reading and writing to the stream.
• Duplex streams → This stream is used to create a stream that is both readable and writable at the same time.

I found this image while browsing the internet, and I believe it perfectly depicts the concept. That's why I thought to include it in this article.

Now, in this article, I will articulate the Duplex stream concept and explore the recent Node.js feature that enables its implementation.

Understanding Duplex Streams

Duplex streams are a fundamental concept in Node.js that allows both reading and writing data simultaneously where the data can flow in both directions independently. Duplex streams are often used for scenarios like network sockets, where data needs to be sent and received concurrently. Unlike Transform streams, which modify data as it passes through, Duplex streams simply pass data back and forth without any transformations. It provides a convenient way to create in-memory communication channels or test applications that rely on bidirectional data flow. If you want to delve deeper into this fundamental concept, I recommend reading through some insightful articles as follows.

https://blog.logrocket.com/creating-duplex-streams-nodejs/

https://www.ramielcreations.com/the-hidden-power-of-node-js-streams

DuplexPair

On August 6, 2024, this significant and a new Node.js API was introduced with the release of version 22.6 to enhance bidirectional stream communication. The DuplexPair API simplifies the creation of these streams, enabling developers to establish in-memory communication channels seamlessly. It achieves this by automatically linking two streams together, allowing data written to one stream to be instantly readable from the other. It has been a coveted feature among the developer community, particularly for scenarios such as:

• In-memory communication: Facilitating communication between different parts of an application without the need for external network connections.
• Testing: Allowing developers to simulate network interactions or other I/O operations in a controlled environment.

By providing a simple and efficient way to establish interconnected streams, DuplexPair not only enhances the development experience with cleaner, more maintainable code, but also improves the efficiency of server-to-server communications.

How DuplexPair Works

The DuplexPair API creates two interconnected Duplex streams: a client and a server. Data written to one stream can be read from the other, making it particularly useful for testing and internal communication within applications. Here’s a brief example of how it operates:

const { DuplexPair } = require('stream');

const { client, server } = DuplexPair();

// Write data to the client
client.write('Hello from client');

// Read data from the server
server.on('data', (data) => {
  console.log('Received on server:', data.toString());
});        

Key Features and Benefits

I briefly mentioned it in the introduction, but let me articulate its key fetures and realtime use-cases with some additional details.

1. Interconnected Duplex Streams: DuplexPair creates two interconnected Duplex streams, allowing data written to one stream to be read from the other. This seamless connection simplifies the management of data flow between components within an application.
2. In-Memory Operation: The DuplexPair API operates entirely in-memory, meaning it does not require network communication. This results in lower latency and higher performance, making it ideal for applications that need fast data exchange without the overhead of network protocols.
3. Simplified API: The API provides a straightforward method to create paired streams, reducing the complexity involved in setting up bidirectional communication. This ease of use allows developers to focus on application logic rather than stream management.
4. Testing Utility: DuplexPair is particularly useful for testing scenarios, enabling developers to simulate network interactions or data exchanges without needing actual network connections. This makes it easier to create unit tests for components that rely on streams.

Now, let me explain how it can benefit various aspects of development and enhance the user experience.

1. Enhanced Performance:By facilitating in-memory communication, DuplexPair minimizes the overhead associated with network latency. This results in faster data processing and improved application performance, particularly in environments where speed is critical.
2. Flexibility in Application Design:The ability to create interconnected streams allows for more flexible application architectures. Developers can design systems that require complex data interactions without the complications of managing separate stream instances.
3. Improved Resource Management:Using DuplexPair reduces the need for additional resources typically required for network communications, such as sockets and external servers. This can lead to cost savings and a more efficient use of system resources.
4. Ideal for Real-Time Applications:The DuplexPair API is well-suited for real-time applications, such as collaborative tools or live data feeds, where low latency and fast data exchange are essential. It enables developers to implement features that require instant communication between different parts of an application.

DuplexPair vs. WebSockets

If you're already a pro in Node.js development, you might be wondering: How is this different from WebSockets or general socket-programming? Why were developers eagerly awaiting such a feature when WebSockets has been around for a long time? Let's dive into this burning question. I think this is the section where you can get your fundamentals clear!

While both DuplexPair and WebSockets facilitate bidirectional communication, they serve different purposes and operate at different levels. I've drafted a comparative table for better understanding.

In a nutshell, DuplexPair is ideal for scenarios where fast, in-memory communication is required, such as internal application logic or testing frameworks. It allows developers to create interconnected streams without the complexities of network communication.

Whereas, WebSocket, is designed for real-time communication across networks, making it suitable for applications that need to maintain a persistent connection for ongoing data exchange. This includes use cases like online games, chat applications, and live data feeds.

Does DuplexPair Crack Down WebSockets?

If you've read through this article, I assume you've found this answer by now. To put it explicitly, the answer is absolutely NO. DuplexPair and WebSockets serve different purposes. Therefore, there is absolutely no chance that DuplexPair will replace WebSockets in the future. Alternatively, you might consider an advanced option like WebTransport, which operates on the QUIC protocol and has great potential to diminish WebSocket usage—but that’s a topic for another upcoming article.

If you liked this article and learned something new, feel free to like, comment, and share it with your network. I firmly believe in the philosophy that sharing is a great way to learn new things. Happy learning!