How Turbopack Chunks Your JavaScript — Starting from the Network tab and working up, a look at chunking strategy and the tradeoffs bundlers make between fewer requests and less code (e.g. 8 chunks can weigh more than 355 do), backed by numbers from bundling the official Next.js site itself.

Sam Poder

Catch Runtime Bugs Before Your JS PR Merges — Greptile now runs your code to find bugs. T-Rex runs your PR branch in a sandbox, uses browser agents to click through your UI, and attaches screenshots and videos as evidence of the issue directly in the PR.

Greptile sponsor

Vitest 5.0 Focuses on Speed and Test Debugging — A major release for the Vite-native test runner, with a benchmark repo showing up to 53% faster runs on dependency-heavy apps. The new Trace View replays Browser Mode tests step by step, and vitest doctor recommends settings to make your suite run faster.

Vitest Team

How Safari Fixed Top-Level await — Safari's module loader was originally built on an abandoned spec proposal and adding top-level await caused years of "cannot access before initialization" errors. Safari 27 brings full spec compliance for it, but it took a ground-up rewrite and this post explains the complexity.

Kai Tamkun (WebKit)

Half Past Fetch: What await fetch() Waits For — Did you know await fetch(url) waits for the headers, not the full body? Gabor digs into some surprising consequences of that for connections, clone(), aborts, and timeouts.

Gábor Koós

Your AI Writes Tests That Pass but Prove Nothing. Fix It — Wallaby CLI makes test generation 10x smarter with live coverage and runtime data, using 3x fewer tokens. One skill to install.

Wallaby Team sponsor

10 Anti-'Slop' Moves for Frontend Projects — A walkthrough of automated checks that cut how much code you have to review, covering OpenAPI codegen, layer boundaries, mutation testing, and using CI to make it all stick.

Yuri Mikhin (Evil Martians)

The Browser's Main Thread is Expensive — A thorough look, complete with demos, at spending your main thread time well, including splitting, batching, prioritizing, and deferring tasks, then getting work off it entirely.

Lee Sun-Hyoup

Dropzone.js 6.x: The Drag and Drop Uploader Returns — A major update for the library that handles the browser side of drag and drop uploading. After a 5 year(!) beta, v6.0, 6.1, and 6.2 landed over two days, bringing no dependencies, smaller bundles, and fixes for chunked uploads that could corrupt files.

Mat Simon

Rslib 1.0: A Build Tool for Shipping JavaScript Libraries — From the Rspack team, a unified build pipeline that handles the irritating parts of publishing packages, like getting ESM and CJS working side by side, Module Federation output, and component CSS across React, Vue, Svelte and Solid.

Chenwei Dai, Elecmonkey, et al.

Balance build time with your time — Our technologists do meaningful work, and we give them the support to have a meaningful life, too.

Fidelity Careers sponsor

vgpu: Render WebGPU Shaders in the Browser or Node.js — Provides a way to use the same shader in the browser or render headlessly with Node (to a high-resolution PNG or MP4 video). WGSL modules import and export like TypeScript does.

Vercel

SimpleWebAuthn 14.0: Now with Post-Quantum Passkeys — The passkeys library now verifies post-quantum ML-DSA passkeys and, on Node 24.7 and up, prefers ML-DSA-44 at registration by default.

Matthew Miller