Toc

The in-page Table of Contents. Long-form pages (docs, MDX articles, rule reference) need a persistent navigation rail that mirrors the heading outline so a reader can both orient themselves and jump. On wide viewports this lives in a right-hand rail…

blog & long-formclient480pxuiv1.0.0

Preview

Toc — live renderprimitives-toc--default

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.

Via shadcn URL
npx shadcn@latest add https://ds.interlace.tools/r/toc.json
With the @interlace alias
npx shadcn@latest add @interlace/toc

Behavior

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.

3 steps, 1 key press — replayed on every PR by the play function of KeyboardFlow. Axe cannot press a key, so this — not the a11y scan — is what proves the component is operable without a mouse.

  1. 1The rail is a named navigation landmark
  2. 2Every heading is a focusable linkTab
  3. 3Each link targets a real heading anchor

Every semantic colour pair this component's own source uses, measured against the shipped hexes in all 4 theme × scheme combinations. The tightest is muted-foreground on background at 7.82:1 (harbor · light), against a floor of 4.5:1.

Measured WCAG contrast ratios per token pair and theme
PairinterlacelightinterlacedarkharborlightharbordarkFloor
muted-foreground on backgroundsecondary copy9.41:111.32:17.82:19.52:14.5:1SC 1.4.3
muted-foreground on cardsecondary copy in a card9.41:110.48:18.25:18.64:14.5:1SC 1.4.3
ring on backgroundfocus ring (SC 2.4.13)8.80:111.79:18.39:110.03:13.0:1SC 1.4.11
ring on cardfocus ring inside a card8.80:110.92:18.86:19.10:13.0:1SC 1.4.11
accent-foreground on accenthover/highlight face8.98:110.46:18.95:19.65:14.5:1SC 1.4.3
foreground on backgroundbody copy19.65:116.97:117.74:116.19:14.5:1SC 1.4.3

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.

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 = 480

Declared, not assumed. Below 480 CSS px the preflight contract draws a dev-mode outline — how to switch it on.

Coverage gate
not in the gate

The 100% gate currently covers src/charts/**/*.{ts,tsx} and src/lib/**/*.{ts,tsx} and src/primitives/{button-variants,data-state-model,meter-scale,skeleton-variants}.ts and src/primitives/{alert,aspect-ratio,avatar,badge,box,breadcrumb,button,callout,card,checkbox,container,data-state,focus-ring,grade-badge,grid,input,label,meter,pagination,published-date,reading-time,section,section-boundary,separator,skip-link,stack,stat-strip,tag,textarea,typography,visually-hidden}.tsx. This file is outside it — the glob widens in phase 7.2.

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.

No release note names this component yet. It shipped with the release above and has not changed since — see the full changelog for what moved elsewhere in the DS.

Import

4 named exports — pull the parts you need.

Public API
import { MIN_VIEWPORT, Toc, TocItem, TocPopover } from '@/components/ui/toc';

Anatomy

Extracted from the primitive's JSDoc header. The source is the only documentation that can't drift.

Toc                                  (nav — data-min-viewport=480)
    └─ <ol data-slot="toc-list">       (top-level heading list)
         └─ <li data-slot="toc-item" data-level="2|3|4" data-active>
              └─ <a data-slot="toc-link" href="#…">
  TocPopover                           (Popover wrapper — data-min-viewport=480)
    ├─ <Popover.Trigger> "On this page"
    └─ <Popover.Content> ⟶ <Toc />

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.

TocProps

Also accepts every <nav> attribute.

PropTypeDescription
items*TocItem[]Ordered list of headings (preserved 1:1 in the rendered list).
labelstringOptional accessible name override. Defaults to "Table of contents".

TocPopoverProps

PropTypeDescription
triggerLabelReact.ReactNodeTrigger label — defaults to "On this page".
triggerClassNamestringClass name applied to the popover trigger button.

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)
Inherited from the preflight focus contract shipped in @interlace/theme.
Reduced motion
Animation is gated on prefers-reduced-motion.
ARIA in the source
  • aria-current
  • 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.

RuleConceptWhere
R4Extends native el + props`React.ComponentProps<'nav'> & TocProps`
R6data-slot on every part`data-slot="toc" / "toc-list" / "toc-item" / "toc-link"`
R7className merged + ...rest`cn(BASE, className)` + `{...rest}` on root nav
R8No `isXxx`; enums for levels`level: 2 \
R10Composition seam`TocPopover` wraps `Toc` via `<Popover>` parts
R14Declares min viewport`data-min-viewport={String(MIN_VIEWPORT)}` + exported const
R18Tailwind onlyZero inline `style`; utility classes + cva
R19Tokens only`pl-md` / `pl-lg` spacing, semantic color tokens
R20AA contrast`text-muted-foreground` / active `text-foreground`
R25Client componentHooks (`useEffect`, `useState`) + `useReducedMotion` → `'use client'`
R26A11y from native el`<nav aria-label>` landmark + `<ol>/<a>` semantics

Minimum viewport

This primitive declares MIN_VIEWPORT = 480 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.

Opt-in to the dev-mode warning
<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

Source

The full implementation — components/ui/toc.tsx once installed.

288 lines · TypeScript
'use client';

import * as React from 'react';

// @interlace/toc v1.0.0 — Interlace design system.
// Docs, props and live preview: https://ds.interlace.tools/c/toc
// What changed since: https://ds.interlace.tools/c/toc#history
// Generated banner — keep it, the upgrade diff reads this version.

/**
 * @interlace/ui — Toc + TocPopover
 *
 * The in-page Table of Contents. Long-form pages (docs, MDX articles, rule
 * reference) need a persistent navigation rail that mirrors the heading
 * outline so a reader can both orient themselves and jump. On wide
 * viewports this lives in a right-hand rail (`Toc`); on narrow viewports
 * it folds into a popover trigger (`TocPopover`) so the content column
 * keeps the full reading width.
 *
 * Two contracts make this primitive non-trivial:

…268 more lines…

Registry JSON

The raw registry record — what the shadcn CLI fetches.