React.js, part 20: where React is heading — the Activity component and rendering what is offscreen

15 Sep 2026 12:00:00 GMT

The last thread to pull is the one that ties the concurrent work together: React is learning to keep a tree mounted while hiding it, instead of destroying and…

React.js, part 19: the React Compiler in production — the eslint plugin, bailouts, and measuring the win

09 Jun 2026 12:00:00 GMT

Turning on an optimizing compiler is the kind of change that either does nothing or does something surprising. Part 19 is the production checklist for the…

React.js, part 18: testing modern React — React Testing Library, Vitest, and queries that survive refactors

14 Apr 2026 12:00:00 GMT

Modern React made a lot of old testing advice wrong: act warnings, shallow rendering, and snapshot-everything all aged badly once components suspended…

React.js, part 17: startTransition with async functions and the useEffectEvent escape hatch

24 Feb 2026 12:00:00 GMT

Two ergonomic gaps closed by the mid-2020s: transitions that wrap asynchronous work, and a principled way for an effect to read the latest value without…

React.js, part 16: Suspense boundaries in production — streaming, nested fallbacks, and error recovery

13 Jan 2026 12:00:00 GMT

Placing one at the top of the app is the demo version. In production the interesting work is deciding where boundaries go, so that the page streams…

React.js, part 15: document metadata and stylesheets in React 19 — hoisting without a helmet library

30 Sep 2025 12:00:00 GMT

Every React app that cared about SEO shipped a helper library whose job was to move and <meta> tags from wherever a component happened to render into… </article> <article> <h1>React.js, part 14: ref as a prop, ref cleanup, and the refs you should stop writing</h1> <p>15 Jul 2025 12:00:00 GMT</p> For years passing a ref through a component meant wrapping it in forwardRef — a ceremony with no equivalent for any other prop. React 19 removed it: ref is now… </article> <article> <h1>React.js, part 13: useFormStatus and pending states — a submit button that cannot double-submit</h1> <p>22 Apr 2025 12:00:00 GMT</p> Double submissions are the canonical web bug: a slow request, an impatient click, two orders. The traditional defenses — a disabled flag set in one handler and… </article> <article> <h1>React.js, part 12: React 19 Actions and useActionState — the form lifecycle, finally built in</h1> <p>04 Feb 2025 12:00:00 GMT</p> By 2025 the biggest React releases were no longer about new rendering features but about finishing half-built abstractions. React 19 completed the form story… </article> <article> <h1>React.js, part 11: useOptimistic — instant UI on top of a slow server</h1> <p>12 Nov 2024 12:00:00 GMT</p> The fastest interface is the one that never waits. Optimistic UI has always meant the same thing — show the expected result immediately, reconcile when the… </article> <article> <h1>React.js, part 10: the React Compiler — what it memoizes, and when to stop hand-writing useMemo</h1> <p>20 Aug 2024 12:00:00 GMT</p> For a decade the performance advice was "wrap it in useMemo", and for a decade developers got the dependency arrays subtly wrong. The React Compiler is the… </article> <article> <h1>React.js, part 9: Context without the re-render storm — splitting providers and stabilizing values</h1> <p>07 May 2024 12:00:00 GMT</p> Context is the first state-sharing tool everyone reaches for and one of the most common performance regrets. The failure mode is predictable: one big provider… </article> <article> <h1>React.js, part 8: Server Actions — forms that talk to the server without a fetch</h1> <p>13 Feb 2024 12:00:00 GMT</p> A form submission used to be a small ceremony: prevent default, assemble a body, fetch, parse errors, branch on status, set state for each. Server Actions… </article> <article> <h1>React.js, part 7: useDeferredValue and useId — the quiet hooks that fixed real bugs</h1> <p>05 Dec 2023 12:00:00 GMT</p> Not every useful hook arrives with a keynote. Two of them quietly removed whole classes of everyday problems: useDeferredValue gave back the responsive list… </article> <article> <h1>React.js, part 6: useSyncExternalStore — connecting React to the world outside it</h1> <p>26 Sep 2023 12:00:00 GMT</p> Sooner or later a component must render data that React does not own: a browser API, a WebSocket, a global store, matchMedia, navigator.onLine. The old answer… </article> <article> <h1>React.js, part 5: the use() hook and reading a promise in render</h1> <p>20 Jun 2023 12:00:00 GMT</p> For years the rule was absolute: data fetching belongs in an effect, render must be pure. The use hook bends that rule in a controlled way — it lets a client… </article> <article> <h1>React.js, part 4: Server Components arrive — the mental model behind the App Router</h1> <p>14 Mar 2023 12:00:00 GMT</p> React Server Components (RSC) are less a feature than a change of subject. Until 2023 a React component was a function that ran in the browser. With RSC, a… </article> <article> <h1>React.js, part 3: Suspense and useTransition — keeping the UI responsive while data loads</h1> <p>06 Dec 2022 12:00:00 GMT</p> Two concurrent features do most of the work in a modern React app: Suspense (which declares what to show while something is pending) and useTransition (which… </article> <article> <h1>React.js, part 2: why your effect runs twice in development (and what StrictMode is really telling you)</h1> <p>09 Aug 2022 12:00:00 GMT</p> Every developer meets it the same way: a console.log inside useEffect fires twice, or a websocket opens two connections, and the first instinct is a bug in… </article> <article> <h1>React.js, part 1: the React 18 concurrent root — createRoot, automatic batching, and what actually changed</h1> <p>12 Apr 2022 12:00:00 GMT</p> React 18 did not look like a big release from the outside — the component API barely moved — but under the surface it replaced the renderer's core with a… </article> </main></body></html>

React.js — Trust is earned, not given

React.js, part 20: where React is heading — the Activity component and rendering what is offscreen

React.js, part 19: the React Compiler in production — the eslint plugin, bailouts, and measuring the win

React.js, part 18: testing modern React — React Testing Library, Vitest, and queries that survive refactors

React.js, part 17: startTransition with async functions and the useEffectEvent escape hatch

React.js, part 16: Suspense boundaries in production — streaming, nested fallbacks, and error recovery

React.js, part 15: document metadata and stylesheets in React 19 — hoisting without a helmet library