Bun 1.2 Looks Good: A Deep Dive into the JavaScript Runtime Update

Introduction to Bun 1.2

Bun, a Zig-written JavaScript runtime, just dropped version 1.2, and ThePrimeagen is hyped. Known for its all-in-one toolkit—bundler, test runner, package manager—Bun aims to replace Node.js with speed and simplicity. In this video, he reacts to Bun 1.2’s updates, from S3 support to HTML imports, while questioning benchmarks and praising its cloud-first approach. Let’s break it down!

Watch the full review on YouTube!

What’s New in Bun 1.2?

Bun 1.2 brings fresh APIs and stability improvements:

• Node.js Compatibility: Supports FS, Net, HTTP, plus new additions like Dgram, HTTP2, Server, and Cluster—over 90% of Node’s test suite passed.
• S3 Support: Native S3 object storage API, mimicking bun.file, up to 5x faster than Node.js npm packages.
• Postgres Support: bun:sql introduces a fast SQL client, starting with SQLite and Postgres (MySQL PR in progress).
• Text Lockfile: Swaps binary lockfiles for JSONC (with comments and trailing commas) for easier PR reviews.
• HTML Imports: Simplifies frontend builds by bundling JS and CSS directly from HTML.

“Bun’s erasing the build system nightmare—days instead of months,” ThePrimeagen speculates.

Performance Claims: Hello World vs. Real Workloads

Bun touts a Hello World Express server handling 3x more requests per second than Node.js. ThePrimeagen is skeptical:

• Hello World Critique: “It’s misleading—Node.js has hooks (e.g., Sentry, New Relic) Bun skips, skewing results.”
• Real Test Proposal: He suggests a server-based game with system calls and heavy JS to showcase Bun’s runtime under load.

Bun 1.2’s S3 client, downloading 7,224 KB files 5x faster, impresses him. He theorizes Zig’s native parallelism outpaces Node’s single-threaded JavaScript churn.

Cloud-First Vision

Bun’s cloud-first design shines with S3 and SQL support:

• S3 API: “It’s like a filesystem for the cloud—smart move, like Go’s robust standard library.”
• Bun:sql: Tagged template literals prevent SQL injection, inspired by postgres.js, with native speed.

ThePrimeagen loves the “batteries-included” mentality: “It’s sticky—reducing npm dependencies is a win.”

Node.js Compatibility Progress

Bun 1.2 runs Node’s test suite per change, hitting 90%+ compatibility. ThePrimeagen sees this as a response to feedback, prioritizing stability over flashy features like RSC (React Server Components), which was initially planned.

“They’re not resting on laurels—Node got complacent,” he notes, applauding the competition.

Frontend Simplicity: HTML Imports

HTML Imports streamline frontend development:

• Scan, minify, and bundle JS/CSS from HTML.
• Supports React, TypeScript, and Tailwind out of the box.

“Super convenient—barely an inconvenience,” he enthuses, likening it to static serving with caching.

Lockfile Evolution

Bun ditches binary lockfiles for text-based JSONC:

• Why?: Easier PR reviews, fewer merge conflicts.
• Performance?: Cached installs 30% faster despite the switch.

“Trailing commas—why not, JSON.org?” he quips, praising Bun’s performance focus.

ThePrimeagen’s Take: Bun’s Future

He admires Bun’s mentality: “Maximize performance and convenience—like Odin for games.” Risks like scope creep exist, but he’s optimistic:

• Upside: A robust, dependency-lite ecosystem.
• Downside: Potential maintenance burdens if standards shift (e.g., SQLite’s Turso rewrite).

“Bun’s carving its own path—not just a turbocharged Vite,” he contrasts with Void Zero.

Conclusion

Bun 1.2 impresses with speed, stability, and developer-friendly features. ThePrimeagen sees it as a game-changer for JavaScript, urging Bun to prove itself beyond Hello World. Check out the blog for more details and try it with bun install—it’s just the beginning!