Rewriting Bun In Rust

According to the Bun team, the rewrite is in early planning stages, with no official release date provided. The team emphasized that the transition will be gradual to ensure stability and compatibility with existing features. They also acknowledged that the rewrite could impact plugin ecosystems and existing integrations, which will need to be adapted to the new core.

Potential Impact on JavaScript Runtime Ecosystem

This development could influence the future landscape of JavaScript runtimes by demonstrating how Rust can be used to build high-performance, reliable tools. If successful, Bun’s rewrite may inspire other projects to consider Rust for core performance improvements, potentially shifting industry standards. For developers, this could mean more stable and faster runtimes, but also raises questions about migration and compatibility with existing tools and libraries.

Background on Bun and Rust Integration Efforts

Bun, launched in 2022, gained popularity for its fast startup times and low memory usage, competing with Node.js and Deno. Its core is primarily written in JavaScript with some components in C++. Rust, known for its safety and performance, has been increasingly adopted in systems programming and runtime development. Prior to this announcement, there had been speculation about Bun exploring Rust to improve its core, but no official plans were disclosed until now. The industry has seen other projects, like Deno, incorporate Rust for performance-critical parts, setting a precedent for Bun’s decision.

“Rewriting our core in Rust is a strategic move to improve performance, safety, and developer confidence in Bun.”

— Bun team representative

Uncertainties About Timeline and Migration Challenges

It is not yet clear when the Rust rewrite will be completed or how it will affect existing users. Details about the migration process, potential compatibility issues, or whether the current JavaScript core will be deprecated remain undisclosed. There is also uncertainty about how the community will respond and how third-party tools will adapt to the new core.

Next Steps for Bun and Developer Community

The Bun team plans to release further updates as they progress with the rewrite, likely including alpha or beta versions for testing. Developers should monitor Bun’s official channels for announcements regarding timelines, migration guides, and compatibility notes. Industry observers will be watching to see if the project maintains stability and performance gains during the transition.

Key Questions

Why is Bun rewriting its core in Rust?

The team aims to leverage Rust’s safety features and performance advantages to improve Bun’s stability, security, and speed.

Will existing Bun users need to do anything?

Details are not yet clear, but the Bun team has indicated that the transition will be gradual to minimize disruption. Users should stay tuned for migration updates and compatibility guides.

Could this rewrite affect Bun’s plugin ecosystem?

Yes, the rewrite may require plugins and third-party tools to be updated or rewritten to work with the new core, which could temporarily impact usability.

How does this compare to similar efforts in other runtimes?

Other projects like Deno have incorporated Rust for performance-critical components, setting a precedent that Bun appears to follow with its rewrite plan.

What are the risks of rewriting in Rust?

Major risks include potential delays, compatibility issues, and the challenge of maintaining feature parity during transition.

Source: hn