JavaScript Conferences

JSNation 2023

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JavaScript Runtimes: Node.js, Deno, Bun

Erick Wendel

Node.js Core Team Developer.

Exploring the World of JavaScript Runtimes

JavaScript runtimes have been a hot topic among developers, with multiple new entrants such as Deno and Bun. Despite the emergence of these new tools, Node.js continues to be a steadfast option. But what makes one runtime different or better than another? A significant factor is how each handles data, particularly when interfacing with the operating system.

Node.js has been around since 2009, offering a robust platform for JavaScript developers. It exposes APIs that allow developers to manage tasks efficiently. The community around Node.js has been strong, encouraging contributions and maintaining its relevance.

Newer runtimes like Deno and Bun are built with modern technologies, such as TypeScript and Rust, aiming to offer enhanced performance and developer experience. While these may use different programming languages or data handling techniques, they often share similar underlying principles.

The Magic Behind Node.js

The inner workings of Node.js reveal its reliance on tools like V8, libuv, and C++. V8 is the JavaScript engine responsible for interpreting code, while libuv handles asynchronous I/O operations. C++ acts as a bridge between JavaScript and the operating system.

Node.js cleverly injects functionality into V8, allowing it to extend JavaScript capabilities. Functions like setTimeout and setInterval, common in JavaScript development, are not native to the language but are implemented via Node.js's C++ bindings. Understanding this architecture helps demystify the power and flexibility of Node.js.

Recreating Node.js from Scratch

Rebuilding Node.js from scratch provides valuable insights into its components and architecture. This process involves compiling V8, linking libraries like libuv, and configuring C++ to handle JavaScript commands. It highlights the complexity and innovation behind Node.js's design.

By experimenting with Node.js's core, developers can appreciate the seamless experience it offers. It also sheds light on how Node.js has evolved from a proof of concept to a staple in web development. The journey involves numerous challenges, but the outcome is a deeper understanding of how JavaScript runtimes operate.

The Role of Community and Collaboration

The strength of Node.js lies not just in its technology but in its community. Collaborative efforts have driven improvements in performance and functionality. The community's willingness to share knowledge and resources ensures Node.js remains a viable option for developers.

Developers behind newer runtimes like Bun and Deno often have roots in Node.js, showcasing a spirit of collaboration rather than competition. This interconnectedness fosters innovation, allowing each runtime to learn from the others' successes and challenges.

Performance and Developer Experience

Performance is a key differentiator among JavaScript runtimes. While Bun claims to be faster due to its use of Zig, Node.js has made strides in optimizing its performance over its various iterations. The focus is not just on speed but also on providing a seamless developer experience.

Tools like TypeScript integration and built-in testing frameworks contribute to Deno's appeal. These features simplify the development process, allowing developers to focus on building applications rather than managing configurations.

The Future of JavaScript Runtimes

The landscape of JavaScript runtimes is dynamic, with each offering unique advantages. Node.js, with its rich history and community support, continues to be a reliable choice. Meanwhile, Deno and Bun bring fresh perspectives and innovations to the table.

Ultimately, the choice of runtime depends on factors like project requirements, performance needs, and developer preferences. Understanding the strengths and intricacies of each runtime empowers developers to make informed decisions and leverage the best tools for their projects.

Watch full talk with demos and examples:

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 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 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.

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 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.

node.js case study

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.

Available in Español: Bun, Deno, Node.js? Recreando un tiempo de ejecución de JavaScript desde cero

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!

3. Node.js Components and Experimentation

I tried finding GitHub projects, but they only did V8 and never used all the components. I wanted to experiment and went to the Node.js website, but it wasn't enough. I found the first Node.js version on GitHub and realized it was just a proof of concept. Now let's talk about the main components: JS, V8, C++, and libuv. The event loop is the magic in libuv, and the C++ bridge connects everything. If we have a JS file with just 'print', it won't work.

4. Implementing Functions in V8

When you compile V8 from scratch, the global list of JavaScript is empty. We can extend V8 on the C++ side and implement functions using annotations of V8. This allows us to call C++ functions from JavaScript.

5. Implementing setTimeout in Node.js

On the setTimeout side, it's exactly the same thing. I have to create the C++ function now, and then I can use uvtimerstart, just to reference that we are using libuv to create and to call those functions. I'm injecting a function on the global state, now the global disk has the setTimeout, and the V8 now thinks that setTimeout was always there. It's pretty great how Node.js is working. If you want to create your runtime, you've got to focus on creating your own implementations.

6. Execution Pipeline and Calling console.log

Let's explore the execution pipeline of Node.js and how it works behind the scenes. We start by reading a file, compiling the JavaScript code into C++ instances, and running the code. Then, we wait for events in the event loop. It's interesting to note that calling console.log relies on the environment and is not part of JavaScript itself.

7. Surprises with setTimeout and setInterval

But if I try printing the console, I'm going to see there's an object there. Pretty weird. If I use object keys, I'm going to see all the console API, all the methods, they are there, but they are just not useful. What if we try using setTimeout? Exactly the same problem. SetTimeout doesn't exist. So Node.js is injecting a bunch of stuff in V8. If you want to have your own browser on your runtimes, there are other working groups that can advise you how you could implement your own functions. On ECMAScript, we have all the grammar and all the things how JavaScript should be executed. Let's try using this print and inject on the V8 context so we can see it working in practice. We can use date, strings, and all the complex objects in JS. Promises are part of JavaScript, but they are there just to be wrappers for callbacks. Well, let's try implementing now this setTimeout.

8. Linking Elements with libuv and C++

To link both elements, we create a function using libuv. We check if it's a callback function and use a getter structure in C++ to save the variables for future execution. We use uw timer, a libuv call, and when the timeout ends, we call the callback function. There's no JavaScript here, just C++. It's amazing to think about embeddables and other cool concepts.

9. Event Loop and Extending V8

The event loop, waitForEvents, and extending V8 are straightforward. By compiling and executing the code, the timeout becomes available on the JavaScript side. Abstractions for setInterval and setTimeout are created using promises and async await, eliminating the need for callbacks. Everything follows the ECMAScript specification.

10. JavaScript Runtimes and Collaboration

My friends, I cannot tell you how was my feeling when I saw those logs working for the first time. Node.js has a bunch of methods. They expose some APIs that are on the C++ side and you can handle from JavaScript. Why do we have so many JavaScript runtimes appearing now? Dino, Bun, and Node.js are doing the same thing but handling data differently. Developer experience matters. There is no competition, as developers from different runtimes collaborate together. Go to the tutorial and see for yourself.

Continuing with Node.js and Bun

If you want to see more content, go to my website. I built an ebook for you and put a challenge to implement your own FS red file. Node.js has a great community and continues to evolve. It's still fast compared to newer runtimes. Bun is said to be faster than Node.js, but the programming language they chose is different - Zig.

Exploring Node.js and Writing a Book

I found the time to explore Node.js and write a book because it was a good opportunity for me to learn and create unique content. Despite the delays and challenges, it was worth it in the end. I'm planning to work on a React Native clone, which will be a complex and exciting project.

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