The Weekly Dev's Brew #21 ☕

Next.js 15.4: Turbopack's Production Readiness Push

The Next.js team has shipped version 15.4, marking a crucial milestone in Turbopack's journey toward production stability. The headline feature: Turbopack builds now pass all 8,298 integration tests for production builds and powers vercel.com itself.

What Actually Matters:

Turbopack Builds reach 100% integration test compatibility for next build --turbopack, representing a crucial milestone toward marking Turbopack stable in Next.js. The team is now focused on finishing bundling optimizations via production chunking and fixing reported bugs from early Alpha adopters.

Stability Improvements include numerous under-the-hood enhancements to both Next.js and Turbopack, with the team confident that Turbopack will soon be ready for production use. They're working toward a beta release in Next.js 16.

Looking Ahead: Next.js 16 promises some significant changes, including Cache Components (beta) that consolidate experimental caching features like Dynamic IO, use cache, and Partial Prerendering into a unified cacheComponents flag. Turbopack Builds will move to beta status, having been validated internally on high-traffic sites like vercel.com.

The trajectory is clear: Next.js is systematically building toward a TypeScript-first, performance-optimized future. The fact that they're dogfooding Turbopack on their own infrastructure gives real confidence in its readiness.

🎙️ New Podcast Episode Alert

This week's episode features Michael Arnaldi, author of Effect TS, tackling a controversial truth: JavaScript's async model is fundamentally broken. From promises that lie about their errors to the nightmare of production-grade error handling, we explore why traditional JavaScript tools set us up for failure.

Key Discussion Points:

• Why JavaScript's async model creates more problems than it solves

• How Effect TS offers a radically different approach built on TypeScript principles

• The "contagious" nature of Effect and why some of the biggest companies are betting their backends on TypeScript-first solutions

This isn't about hot takes—it's an honest conversation about the hard truths of building reliable systems in JavaScript. Perfect for your next 50 minute long coffee break.

📺 Watch on YouTube

🎧 listen everywhere you can find podcasts

Quick Sips ☕

Formisch Form Library: A new schema-based, headless form library for JavaScript frameworks has emerged, promising type safety with autocompletion, fast performance with fine-grained DOM updates, and a minimal API. Built by Fabian Hiller (author of Valibot) with Valibot integration and small bundle sizes starting at 2.5 kB, it's worth watching for teams frustrated with current form solutions (so basically everyone).

Rolldown-Vite Performance Benchmarks: VoidZero's performance data is genuinely impressive. Projects are seeing 3x-28x build speed improvements when migrating from current Vite to Rolldown-powered Vite. Notable wins include Outline seeing 22.3x improvement (47.27s → 2.12s) and various projects reporting significant memory usage reductions. The Rust-based bundler is showing real promise for larger codebases.

React History Deep Dive: Corbin Crutchley wrote down an excellent exploration of React's development philosophy, revealing how the team's decisions have remained remarkably consistent since its earliest days. The piece traces everything from JSX and the virtual DOM to hooks, concurrent features, and server components—showing how each innovation built naturally on previous foundations. Worth reading for understanding why React's APIs feel the way they do.

JavaScript Date Quirks: Speaking of consistency, Sam Rose created a quiz highlighting JavaScript's... interesting Date class behaviors. Everyone knows that the Date API could be better, but let’s see how much you actually know about Dates!

☕ Barista's Brew Tip

Cold Brew Concentrate Ratios: Use a 1:4 coffee-to-water ratio for concentrate, then dilute 1:1 with cold water or milk when serving. This gives you maximum flexibility and prevents over-extraction from sitting too long. Much more reliable than your average dependency update.

See you next week. Happy coding & brewing!