JavaScript Runtimes: Node.js vs Deno vs Bun

  • JavaScript runtimes extend JavaScript's capabilities by bridging with languages like C++ and Rust.
  • The differences in runtime performance stem from how data is handled and communicated with the operating system.
  • Node.js remains relevant due to its active community and ongoing performance improvements.
  • Node.js uses V8, C++, and libuv to execute JavaScript, extending its functionality with custom implementations.
  • Understanding low-level implementations enhances development skills and offers insights into runtime functionality.

Embarking on a journey to understand the inner workings of JavaScript runtimes offers a unique perspective on how modern web development tools operate. Exploring the core components and mechanisms of runtimes like Node.js, Dino, and Bun reveals the intricate dance between JavaScript, C++, and other languages. This exploration not only enhances our technical skills but also deepens our appreciation for the technologies we often take for granted.

JavaScript runtimes such as Node.js serve as an interface between JavaScript and lower-level languages like C++. They allow developers to execute JavaScript code by compiling it into machine-readable instructions and extending its capabilities with additional functions. Node.js, for instance, uses V8 as its engine to interpret JavaScript and leverages C++ to bridge interactions with the operating system. This setup enables JavaScript developers to perform tasks that typically require lower-level programming expertise.

The emergence of new JavaScript runtimes like Dino and Bun has ignited discussions around performance and developer experience. These runtimes offer different approaches to handling data and interactions with the operating system, leading to variations in speed and efficiency. Dino, for example, uses TypeScript and Rust to compile JavaScript into executable code, aiming to enhance security and developer productivity. Similarly, Bun employs JavaScript core to optimize data handling and execution speed.

One key aspect that sets these runtimes apart is how they manage file system APIs and data buffers. The efficiency of data transfer between the runtime and the operating system can significantly impact performance. For instance, Bun claims to outperform Node.js by utilizing alternative programming languages and techniques to streamline data processing. As developers, understanding these differences helps us make informed choices when selecting a runtime for our projects.

Despite the growing competition, Node.js continues to thrive due to its robust community and ongoing improvements. The introduction of a performance working group has led to significant speed enhancements in recent versions, demonstrating the project's commitment to staying relevant. Node.js's extensive ecosystem and adherence to ECMAScript specifications make it a reliable choice for many developers, even as new runtimes emerge.

Behind the scenes, Node.js relies on several key components to execute JavaScript code. V8, the JavaScript engine, transforms code into a format that can be understood by the machine. C++ acts as a bridge, facilitating communication between JavaScript and the operating system. Libuv, another critical component, handles asynchronous operations and event loops, enabling Node.js to manage tasks like file I/O and networking efficiently.

Exploring the foundational elements of Node.js reveals the complexity involved in creating a runtime from scratch. By delving into the source code and understanding the interactions between different components, developers can gain valuable insights into how JavaScript runtimes function. This knowledge not only enhances our technical proficiency but also empowers us to contribute to the development of new tools and technologies.

The process of extending JavaScript's functionality involves injecting custom implementations into the runtime's environment. For example, functions like setTimeout and setInterval are implemented in C++ and exposed to JavaScript through the runtime. This approach allows developers to create powerful applications using familiar JavaScript syntax while leveraging the performance benefits of lower-level languages.

By experimenting with runtime implementations and exploring the source code, developers can uncover the nuances of JavaScript execution. This hands-on experience provides a deeper understanding of how runtimes optimize code execution and manage resources. It also highlights the importance of collaboration between different runtime projects, as developers from Node.js, Dino, and Bun often share knowledge and contribute to each other's work.

In the ever-evolving landscape of web development, understanding the inner workings of JavaScript runtimes is a valuable skill. It equips developers with the knowledge needed to navigate the complexities of modern software development and make informed decisions about the tools and technologies they use. By embracing this exploration, we can unlock new possibilities and contribute to the continued evolution of the JavaScript ecosystem.

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From Author:

Bun, Deno, and many other JavaScript runtimes have been hype, but do you know why? Is it that easy to make a runtime from scratch?


I've been researching the secret behind Node.js' power and why there are so many new JavaScript runtimes coming up. Breaking down each key component used on Node.js I've come to interesting conclusions that many people used to say whereas in practice it works a bit differently.


In this talk, attendees will learn the concepts used to create a new JavaScript runtime. They're going to go through an example of how to make a JavaScript runtime by following what's behind the scenes on the Node.js project using C++. They'll learn the relationship between Chrome's V8 and Libuv and what makes one JavaScript runtime better than others.

This talk has been presented at JSNation 2023, check out the latest edition of this JavaScript Conference.

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FAQ

The speaker suggests extending the V8 engine by implementing custom functions in C++ and linking them to JavaScript calls, effectively adding new functionalities like 'print' and 'setTimeout' to the V8 global context.

The speaker faced significant challenges, including the complexity of understanding and implementing the various components of Node.js, coordinating with experts, and the time-intensive nature of compiling and managing the required environments and libraries.

The speaker encourages taking pictures and mentioning the event on social media to help promote their work and extend the reach of the event, aiding in community building and recognition.

The key takeaway was the realization that Node.js extends functionalities by linking JavaScript with C++ operations, demonstrating that much of what seems complex is manageable with the right understanding and tools.

The speaker mentions an upcoming project to recreate React Native, indicating plans to explore and understand another complex framework by breaking it down into its fundamental components.

The speaker was motivated by a fear of being asked detailed questions about Node.js's inner workings at conferences and realized a gap in his knowledge. This led him to deeply explore and recreate Node.js to understand it better.

In the reconstruction of Node.js, the main components used were JavaScript for scripting, the V8 engine for JavaScript interpretation, C++ as a bridge for connecting JavaScript with the operating system, and libuv for managing event loops and asynchronous operations.

The tutorial and all related resources, including slides and links, are provided in the last slides of the presentation discussed in the talk.

Erick Wendel
Erick Wendel
28 min
01 Jun, 2023

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Video Summary and Transcription
This Talk explores the journey of learning and recreating Node.js from scratch, highlighting the main components and experimentation involved. It delves into implementing functions in V8 and setTimeout in Node.js, as well as the execution pipeline and the event loop. The collaboration between different JavaScript runtimes and the continuing evolution of Node.js are also discussed. The speaker shares their experience of exploring Node.js and writing a book, and hints at future projects involving React Native.

1. Introduction to Node.js and My Journey of Learning

Hello, everyone. We're gonna make some crazy experiments today. I tried recreating Node.js from scratch and I'm going to tell you all the step-by-step. First of all, all the slides, all the links, references and even a tutorial for you to follow after this conference I put on the last slides. Mention me, mention the event because this is how you can push our job further. Well, all this talk is about, do I really know Node.js? So I start researching a lot of things and start making questions. I've been creating a bunch of videos doing the same ideas. But this talk, I already have a tutorial there and here today I'm going to show you some highlights, and I even wrote a blog post for you later to extend.

2. Introduction to Node.js and My Journey

I'm not a C++ developer, but I'm curious and eager to learn. This research is my own, and I had to reach out to Google for help. Shout-out to Ben, Dino, Node.js, and the creators for their amazing job. They abstract the complexity, allowing us to create powerful applications. Let's do some magic!

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