Interactions

small product moments with real physics underneath · 10 entries

#File1 of 10

01 · ai-prompt-box.tsx

AI prompt · animated border + mode pills

02 · agent-plan.tsx

agent · thinking

0/5

Parse query

Search knowledge

Synthesize answer

Cite sources

Format response

Agent plan · streaming task nodes with beam

03 · spotlight-card.tsx

newv2.4.0

Real-time collaboration

Multiplayer cursors, live presence indicators, and sub-50ms sync for every keystroke. Built on CRDTs, invisible until it matters.

Learn more→

Spotlight card · cursor-following glow + 3D tilt

04 · spark.tsx

cpu · 60s78%

Spark · sparkline library

05 · reflow.tsx

reflow0 lines · 240px

predicted height0px

Reflow · drag to resize, text reflows at 60fps

06 · bubble.tsx

tight wrap

Hey, have you tried the new layout engine?

Not yet — is it the one that does text measurement without touching the DOM?

Yeah. You call prepare() once and then layout() is pure arithmetic. Resize is basically free.

That's wild. So no getBoundingClientRect in a loop?

Zero. Canvas measureText for the initial pass, then it's all numbers.

Shipping it.

Bubble · binary-search shrink-wrap via pretext

07 · accordion.tsx

accordion…

A text measurement and layout library. It calls canvas measureText once in prepare(), then every subsequent layout() call is pure arithmetic — no DOM access, no reflow. Resize-driven relayout is essentially free.

The core insight: segment the text and measure each segment once via the canvas font engine. Cache the widths. From there, line breaking is just arithmetic over cached numbers — you're adding widths until you exceed the max, then wrapping.

Every call to getBoundingClientRect or offsetHeight triggers a synchronous layout reflow — the single most expensive operation the browser does. If you need to measure 200 text blocks for a virtual list, that's 200 reflows. Pretext does it in zero.

Pretext validates against Chrome, Safari, and Firefox across 4 fonts, 8 sizes, 8 widths, and 30 multilingual texts. The measurement uses the browser's own font engine as ground truth via canvas — it's not approximating.

Accordion · precise height via pretext, no max-height hacks

08 · flow.tsx

flow0 lines · 252px

prepare 1×layout 60fpsDOM reads 0

Flow · ambient reflow at 60fps, zero DOM measurement

09 · dock.tsx

Dock · cosine-windowed magnification · Compass · ×1.00

10 · particle-search.tsx

Particle search · backspace effects

? keys · ⌘K palette · esc back