Section Boundary
The "stream per section" primitive. Fuses React Suspense + a class-based ErrorBoundary into one component so a template can render section-by-section with per-section skeleton + per-section error fallback. The page paints whatever's ready; slow / failed…
Preview
Rendered from the story the storybook (a11y) CI gate runs axe against — the preview can't show something that hasn't been verified.
Install
Two equivalent paths — the URL works in any shadcn-CLI setup; the alias works once you've registered @interlace in your components.json.
npx shadcn@latest add https://ds.interlace.tools/r/section-boundary.jsonnpx shadcn@latest add @interlace/section-boundaryBehavior
What this component does — the keyboard path, the measured colour, the text equivalent and the states it can be in. Every figure below is read out of the test or the source that enforces it by scripts/build-behavior-map.mjs, so nothing here can outlive the gate that keeps it true.
Measured contrast
packages/ui/__tests__/theme-contract-lock.test.ts ↗Every semantic colour pair this component's own source uses, measured against the shipped hexes in all 4 theme × scheme combinations. The tightest is destructive on background at 7.60:1 (harbor · light), against a floor of 3:1.
| Pair | interlacelight | interlacedark | harborlight | harbordark | Floor |
|---|---|---|---|---|---|
| destructive on backgrounddestructive tint on the page surface | 8.31:1 | 10.43:1 | 7.60:1 | 10.03:1 | 3.0:1SC 1.4.11 |
| destructive on carddestructive tint inside a card | 8.31:1 | 9.66:1 | 8.02:1 | 9.09:1 | 3.0:1SC 1.4.11 |
Text pairs are held to 4.5:1 (WCAG 2.2 SC 1.4.3); borders, rings and chart axes to 3:1 (SC 1.4.11 non-text). Bold is the worst cell in the row — the one a brand fork has to keep an eye on.
Runtime contract
packages/ui/vitest.config.ts ↗Where it renders, how narrow it survives, and whether its lines are inside the coverage gate — three answers a consumer needs before the paste, not after the bug.
- Render boundary
'use client'Hydrates. It brings JavaScript to any route that imports it — put the boundary here, not at the page.
- Minimum viewport
MIN_VIEWPORT = 320Declared, not assumed. Below 320 CSS px the preflight contract draws a dev-mode outline — how to switch it on.
- Coverage gate
100% × 4Inside the v8 gate: lines 100, statements 100, functions 100, branches 100. A threshold under 100 only records how much you stopped caring, so there isn't one.
History
This component is at v1.0.0, first shipped in @interlace/ui 1.0.0. The version is stamped as a banner into the file the install writes, so the copy in your tree says which one you have — compare it with the number above before deciding whether to re-run the install.
@interlace/ui 1.0.01 entry
- Addedminor
The five-layer architecture lands: primitives → patterns → charts → templates, with
SectionBoundaryas the composition seam and thirteen full-page templates installable as registry blocks.Components- @interlace/article-template
- @interlace/auth-template
- @interlace/author-template
- @interlace/blog-home-template
- @interlace/dashboard-template
- @interlace/docs-page-template
- @interlace/error-template
- @interlace/landing-template
- @interlace/registry-item-template
- @interlace/scorecard-template
- @interlace/settings-template
- @interlace/stats-template
- @interlace/tag-template
Import
2 named exports — pull the parts you need.
import { MIN_VIEWPORT, SectionBoundary } from '@/components/ui/section-boundary';Anatomy
Extracted from the primitive's JSDoc header. The source is the only documentation that can't drift.
<section data-slot="section-boundary" data-name="…" data-min-viewport="320">
<Suspense fallback={skeleton}>
<ErrorBoundary fallback={error}>
{children}
</ErrorBoundary>
</Suspense>
</section>API reference
Parsed from the type declarations in the source — the same file the install writes into your tree, so this table can't drift from the component you get.
SectionBoundaryProps
Also accepts every <section> attribute.
| Prop | Type | Description |
|---|---|---|
| name* | string | Telemetry-grade name for this section ("article-header", "registry-item-variants"). Required so error reporters / Sentry breadcrumbs / a11y screen-reader announcements have a stable handle. Also projected to the DOM as `data-name` so playwright E2E + manual QA can `await page.locator('[data-slot="section-boundary"][data-name="article-header"]')` without coupling to className. |
| skeleton | React.ReactNode | Loading-state UI surfaced while children suspend. Defaults to a generic full-width `<Skeleton variant="card" />`. Pass a shape-matched variant via `skeletonVariant` for a one-prop swap, or pass an arbitrary ReactNode via `skeleton` for full control. |
| skeletonVariant | SkeletonVariant | Shortcut for the common case — picks a `<Skeleton variant>` shape. |
| error | React.ReactNode | Error-state UI surfaced when children (or any descendant) throws. Defaults to a minimal `<p role="alert">Section failed to load.</p>` styled with `text-destructive`. Pass a React node — including a `<button onClick={retry}>` — to give the user a recovery path. NOTE: rendering a different fallback after recovery requires a remount (the boundary's error state is one-shot). For retry-on-click patterns, wrap children in a key-based forced remount. |
| children* | React.ReactNode | — |
SectionErrorBoundaryProps
| Prop | Type | Description |
|---|---|---|
| fallback* | React.ReactNode | — |
| name* | string | — |
| children* | React.ReactNode | — |
Accessibility
Every story for this component is rendered headlessly and checked with axe-core (wcag2aa, wcag22aa, best-practice, ACT) on every PR. That gate has no continue-on-error, so what ships has zero known violations.
What follows is what static analysis can see. Axe cannot press a key and never sees an overlay open, so the operable-without-a-mouse claim lives in Behavior instead, where the keyboard path is replayed step by step.
- Focus + keyboard behaviour
- Native element semantics — no interaction layer to get wrong.
- Focus ring (WCAG 2.2 SC 2.4.13)
- Not focusable — no focus indicator required.
- Reduced motion
- No animation to gate.
- ARIA in the source
role="alert"role="region"aria-label
Examples
4 more states from the same story file.
R-rule compliance
Every primitive in @interlace/ui models to the portable 26-rule floor enforced by the componentApi ESLint preset. The cells below pin exactly where each rule applies in this file.
| Rule | Concept | Where |
|---|---|---|
| R4 | Extends native el | `React.ComponentProps<'section'>` + section-boundary props |
| R6 | data-slot on root | `data-slot="section-boundary"` + `data-name` |
| R7 | className merged + ...rest | `cn(className)` + `{...props}` on <section> |
| R8 | No `isXxx`; required `name` | `name` required (telemetry surface) — not a boolean |
| R10 | Composition seam (fallbacks) | `skeleton` + `error` slots accept any ReactNode |
| R14 | Declares min viewport | `data-min-viewport={String(MIN_VIEWPORT)}` + exported const |
| R18 | Tailwind only | Zero inline `style`; cn() pass-through |
| R19 | Tokens only | (n/a — primitive renders no visual chrome itself) |
| R20 | AA contrast | (delegated to fallback children — Skeleton + ErrorState own AA) |
| R25 | Client component | Suspense + ErrorBoundary require client tier |
| R26 | A11y | role="region" + aria-label={name} so screen readers can land on each section |
Minimum viewport
This primitive declares MIN_VIEWPORT = 320 CSS px (DESIGN_PRINCIPLES #14). When mounted in a container narrower than this, the preflight contract draws a dev-mode outline so the regression is visible during local development.
<body data-interlace-dev>...</body>
Add the data-interlace-dev attribute to the body in development builds only — preflight then outlines any primitive whose container is below its declared data-min-viewport.
Dependencies
- Base UI primitive
- Native / no Base UI dependency
- Lucide icons
- none
- NPM dependencies
- none
- Registry dependencies
Source
The full implementation — components/ui/section-boundary.tsx once installed.
'use client';
import * as React from 'react';
// @interlace/section-boundary v1.0.0 — Interlace design system.
// Docs, props and live preview: https://ds.interlace.tools/c/section-boundary
// What changed since: https://ds.interlace.tools/c/section-boundary#history
// Generated banner — keep it, the upgrade diff reads this version.
/**
* @interlace/ui — SectionBoundary
*
* The "stream per section" primitive. Fuses React Suspense + a class-based
* ErrorBoundary into one component so a template can render
* section-by-section with per-section skeleton + per-section error
* fallback. The page paints whatever's ready; slow / failed sections
* degrade in place without blocking the rest.
*
* <ArticleTemplate>
* <SectionBoundary name="article-header"> ← header streams
…177 more lines…Registry JSON
The raw registry record — what the shadcn CLI fetches.