Bun: A New Contender in JavaScript Tooling

Explore Bun, a game-changing JavaScript runtime optimizing development while maintaining compatibility. Discover its performance edge, versatile toolkit, and considerations for production use. Is Bun the future of JavaScript tooling? Watch to find out!

Přemysl Ciompa - Full Stack Developer

Table of Contents

The JavaScript tooling landscape is in a state of constant evolution, and recently, Bun has emerged as a promising new JavaScript runtime. For those keen on understanding its capabilities, my recent deep dive provides insights into what Bun offers.

Bun's objective is unambiguous: to optimize the JS development process while ensuring backward compatibility with the existing Node ecosystem. This translates to compatibility with popular libraries and frameworks, but with improved performance and efficiency.

Technically speaking, Bun operates using the JavaScriptCore engine and is developed in Zig. Contemporary development features like watch mode and hot reloading are integrated, enhancing the developer experience. For a more in-depth look into Bun's technical intricacies and standout features, the video provides comprehensive coverage.

Bun boasts a versatile toolkit, serving as a package manager, transpiler, and bundler. It also introduces speedy Bun APIs, designed specifically for tasks such as file system operations, http server and websockets. While the introduction of new opt-in APIs might raise questions in light of the broader existing ecosystem, the demonstration of what's achievable is indeed intriguing.

To investigate the most interesting claims of Bun I decided to a deeper performance tests. The tests proved that Bun consistently outshines Node.js, for most of the use cases it proved to be 1-2x faster. However, where it really shined wre CPU-intensive tasks. In those, the JS core kicked in and we saw up to 10x difference between Bun and Node. Nonetheless, it's crucial to interpret these results in context, especially when juxtaposed against marketing assertions. A more detailed performance analysis can be found in the video, where we dive deeper into specifics of chosen tasks and how they were measured.

From a DevX standpoint, my experience with Bun was a blend of amazement and occasional challenges. Its robust support for TypeScript is just a delight. The feeling that you just "write" typescript without any complex setup is a game changer. This fact in combination with workspace support is just awesome. Everyone who had to maintain complex typescript monorepos with an efficient CI pipeline including e2e, and integration tests really understood the value of these features. That said, developers should be cognizant of the occasional bugs that surface. Eg., it happened to me several times that bun install just stopped working in workspace packages and I needed to reset the .lock file to continue working.

For those mulling over the idea of adopting Bun for production, here are some points to ponder:

- The current lack of support for Windows.

- It's not fully compatible with Node.js.

- Some tools, like Nestjs and TypeOrm, are unsupported due to the absence of decorator support, though this scenario may soon change.

Despite the impressive $7M investment backing Bun, questions surrounding its long-term viability are prevalent. While Bun's community is witnessing rapid growth, it predominantly remains a one-man endeavor. The video delves deeper into these concerns, offering a nuanced perspective.

To wrap up, Bun presents innovative features and avenues in the JS tooling domain. From where I stand, Bun is still in its nascent stages. I'm sufficiently intrigued to use it in my pet projects, but I'd recommend a measure of caution for those pondering its use in production settings.

Brown Bag VideoCode & ToolsJavaScript Engineering

Přemysl Ciompa - Full Stack Developer

Proud new father, problem solver and tinkerer, who loves to learn new concepts, explore new emerging technologies with passion for solving business problems and nuanced technical design.

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