Making React testing library tests 43% faster

Making React testing library tests 43% faster
6 minutes by Scott Cooper

Three performance fixes were made to jsdom that together made a large React test file 43% faster. The biggest fix stops jsdom from scanning all form labels repeatedly, dropping that work from 60ms to under 1ms. Two other fixes correct a selector fast path that was never actually reached, and reduce wasted work when dispatching events. Tests using large forms, many getByRole queries, or lots of user interactions will benefit most.

How dormakaba Modernized a Mission-Critical Security Platform with React and KendoReact
sponsored by Progress Telerik

For a security platform built to last decades, modernization is about more than moving to a new framework. See how dormakaba rebuilt Kaba exos 9300 around React and KendoReact to create a frontend foundation its team could confidently own, maintain and evolve for the long term.

Making referential stability a type
9 minutes by Jovi De Croock

Inline arrays and callbacks passed as props silently break memoization in React, but the type system never warns you. This experiment adds a Stable brand to TypeScript so components can declare that a prop must be a stable reference, pushing the responsibility onto the caller. Strict hook wrappers enforce this at the dependency level with readable error messages, making it useful for both developers and coding agents.

React agentic engineering in 2026
12 minutes by Sascha Becker

AI coding agents confidently produce outdated code because their training data predates your dependencies. The fix is making documentation readable at runtime: Next.js ships its docs inside the package, MUI and Storybook offer server tools for live component access, and skills files give agents explicit project rules. The real bottleneck shifted from writing to reviewing, since generated code that compiles and renders can still be wrong. Correct and good are not the same thing.

Coordinating optimistic updates in Next.js
19 minutes by Aurora Scharff

Overlapping user interactions can cause data to save out of order. Combining useActionState and useOptimistic in React solves this by queuing writes sequentially while showing changes instantly. A shared reducer handles both the optimistic UI update and the server write. If a save fails, the UI automatically rolls back to the last confirmed state without any extra logic.

Building accessible UI with React aria components
6 minutes by Sergio Xalambrí

Retrofitting accessibility after the fact leads to inconsistent results and real barriers for users. React Aria Components solves this by offering unstyled primitives with accessibility built in — handling ARIA attributes, keyboard navigation, and focus management automatically. You compose the structure and add your own styles. It works best for teams building custom design systems where accessibility and control over rendering matter most.

And the most popular article from the last issue was:

• How to find a Next.js memory leak in production