Runtime config

The module writes a public runtime config namespace so the <TableOfContents> component (and your app) can read the same defaults on server and client.

Built in src/module.ts:190, published as:

nuxt.options.runtimeConfig.public.nuxtToc = {
  collection:   string   // default 'content'  (v3 collection)
  depth:        number   // default 2          (rendered depth)
  scrollSpy:    boolean  // default true
  rootMargin:   string   // default '0px 0px -80% 0px'
  smooth:       boolean  // default false
  scrollOffset: number   // default 0
  contentMajor: 2 | 3 | null  // detected @nuxt/content major, or null
}

Type: NuxtTocPublicRuntimeConfig (src/module.ts:73) and augmentation on @nuxt/schema (src/module.ts:91) so useRuntimeConfig().public.nuxtToc is fully typed after npx nuxi prepare.

Reading it in your app

const config = useRuntimeConfig()
console.log(config.public.nuxtToc.collection) // 'content'
console.log(config.public.nuxtToc.contentMajor) // 2 | 3 | null

contentMajor — detection result

Set by detectContentMajor(nuxt.options.rootDir) once at module setup() (src/module.ts:176). Values:

• 2 — host has @nuxt/content@2 installed
• 3 — host has @nuxt/content@3 installed
• null — Content missing or version not 2/3

Used to decide which fetch plugin to register (fetch-v2 vs fetch-v3), and purely informational for you — no app code needs to branch on it if you use pass-in :toc.

// Devtools / debugging helper
if (useRuntimeConfig().public.nuxtToc.contentMajor === null) {
  console.warn('Content not installed — auto-fetch disabled; pass :toc manually')
}

How defaults flow into props

Inside TableOfContents.vue:212 (nuxtTocPublic) the six user-tunable keys are read as fallback when a prop is undefined (example: scrollSpyEnabled at line 244, resolvedRootMargin at line 251, etc.):

Runtime value	Prop fallback	Normalization point
collection	props.collection || nuxtToc.collection || 'content'	fetch-v3.ts:39 guards empty string again
depth	resolveEffectiveDepth(props.depth ?? nuxtToc.depth, isSublistShown)	limit-toc-depth.ts:113
scrollSpy	props.scrollSpy ?? nuxtToc.scrollSpy	scrollSpy !== false
rootMargin	props.rootMargin || nuxtToc.rootMargin	observer options.rootMargin
smooth	props.smooth ?? nuxtToc.smooth → !!	scroll-to-heading.ts:58
scrollOffset	max(0, floor(props.scrollOffset ?? nuxtToc.scrollOffset))	scroll-to-heading.ts:50

Passing a prop always wins over the runtime value; runtime value wins over the built-in default. See Module options (how to set the runtime values) and Props (per-component overrides).

Tweaking at runtime vs at build

• Build-time / config-time: edit nuxt.config.ts → nuxtToc — requires restarting dev.
• Client-side only: you can still override per-component props dynamically (bind to a ref) — the component watches observedIdsKey, resolvedRootMargin, scrollSpyEnabled, and hasLinks and rebuilds the observer on the next requestAnimationFrame.

Log and warning behavior tied to this config

• If Content is installed (contentMajor != null) but not registered in modules, the module logs [nuxt-toc] @nuxt/content is installed but not registered… during setup.
• If contentMajor == null, it logs [nuxt-toc] @nuxt/content v2 or v3 not found. Auto-fetch disabled; pass :toc….
• The fetch plugins (fetch-v2.ts:31, fetch-v3.ts:31) also warn when path is empty, and on caught fetch errors — only in import.meta.dev.

Next: Types and Module options for the full set of typed keys.