Writing
Notes on frontend engineering, performance, animation, and the decisions behind shipped work.
A nested grid normally invents its own tracks. Subgrid makes it reuse the parent's instead, which fixes card rows, but also removes the implicit grid and lets padding leak into parent sizing.
ES2025 puts base64 and hex codecs on Uint8Array itself. What the four methods do, why lastChunkHandling decides whether your decoder validates anything, and what I measured.
JavaScript Set finally ships union, intersection, difference and three predicate methods. The set-like protocol, the ordering rules, and the reference-equality trap.
The Web Locks API gives you cross-tab leader election with no heartbeat, no TTL, and no dependencies. A practical tour of modes, ifAvailable, signal, and why steal is a loaded weapon.
Temporal splits JavaScript's one vague Date into precise types. Measured DST behaviour in Node 26, and where the adoption claims in this year's blog posts get the browser versions wrong.
The URL Pattern API replaces per-framework route matchers with one standardized grammar — and Node's native implementation diverges from the spec in one narrow case.
The v flag rewrites JavaScript's character-class grammar: intersection with &&, subtraction with --, nested classes and properties of strings. What shipped, and what breaks on upgrade.
Iterator helpers map, filter and take over a Map, a generator or an infinite sequence without ever spreading it into an array — plus the one footgun that shares its source.
Cascade layers make the layer itself a design decision, so specificity becomes a local concern inside a layer instead of a global arms race across your whole stylesheet.
@starting-style gives a first-render element a state to transition from, and allow-discrete lets display flip mid-transition. Together they replace the mount-class dance.
@property upgrades a CSS custom property from an untyped token stream to a typed, validatable, interpolable value — and the rules are stricter than they look.
Intl.Segmenter replaces the whitespace split with locale-aware segmentation: graphemes, words and sentences as the browser defines them.
moveBefore() adds the DOM's missing move primitive: nodes relocate without the implicit remove-and-insert that resets iframes, focus, animations and dialogs.
The @scope at-rule limits selector reach in pure CSS — and adds scoping proximity, a zero-weight & rewrite, and a hard line between selector and style isolation.
The Popover API is a browser-level overlay protocol: one attribute owns stacking, dismissal, focus order and events — no positioning library, no close listener.
AbortSignal is not just fetch() cancellation — it is a general protocol for stopping async work, with a typed reason, composable signals, and standard teardown.
content-visibility lets the browser skip layout and paint for off-screen content, while contain-intrinsic-size keeps the scrollbar honest. What auto skips and where the gains disappear.
How the Speculation Rules API lets the browser prefetch or prerender the page a visitor is about to open — and what your code must stop doing to be safe to render ahead of time.
CSS scroll-driven animations swap an animation's clock timeline for scroll position: how animation-timeline, scroll(), view(), and animation-range work, and where the support floor sits.
How the Popover API and CSS anchor positioning replaced JavaScript positioning libraries: tethering, position-area, edge fallbacks, and the support floor.
How scheduler.yield() hands the main thread back without losing your place in the task queue — with cross-browser fallbacks and LoAF measurement.
Container queries let components adapt to their own space instead of the viewport. Learn how to build truly reusable responsive UI with modern CSS, including fallbacks and real-world patterns.
A progressive-enhancement pattern for adding polished route and panel transitions while keeping state, accessibility, and fallbacks under your control.