feat: add error code documentation routing

app/pages/docs/[...slug].vue

@@ -79,7 +79,7 @@ watch(page, (page) => {
 }, { immediate: true })
 
 // Get the -2 item of the breadcrumb
-const currentSectionTitle = computed(() => headerLinks.value[0].children.find(link => path.value.includes(link.to))?.label || findPageBreadcrumb(navigation.value, path.value).slice(-1)[0].title)
+const currentSectionTitle = computed(() => headerLinks.value[0].children.find(link => path.value.includes(link.to))?.label || findPageBreadcrumb(navigation.value, path.value).slice(-1)[0]?.title || page.value?.title)
 
 const breadcrumb = computed(() => {
   const links = mapContentNavigation(findPageBreadcrumb(navigation.value, path.value)).map(link => ({

content.config.ts

@@ -10,7 +10,8 @@ const docsV3Source = {
 
 const docsV4Source = {
   cwd: process.env.NUXT_V4_PATH ?? undefined,
-  repository: !process.env.NUXT_V4_PATH ? 'https://github.com/nuxt/nuxt/tree/4.x' : undefined,
+  // TODO: revert to 4.x branch before merging
+  repository: !process.env.NUXT_V4_PATH ? 'https://github.com/nuxt/nuxt/tree/error-context' : undefined,
   include: 'docs/**/*',
   exclude: ['docs/**/*.json'],
   prefix: '/docs/4.x'

nuxt.config.ts

@@ -117,6 +117,7 @@ export default defineNuxtConfig({
     '/docs/3.x/getting-started/introduction': { prerender: true },
     '/docs/4.x/getting-started/introduction': { prerender: true },
     '/docs/5.x/getting-started/introduction': { prerender: true },
+    '/docs/4.x/errors': { prerender: true },
     '/modules': { prerender: true },
     '/modules/**': { isr: 60 * 60 },
     '/changelog': { isr: 60 * 60 },

server/middleware/error-docs-redirect.ts

@@ -0,0 +1,19 @@
+/**
+ * Redirect unversioned error doc paths to the current default version.
+ *
+ * The Nuxt runtime links to https://nuxt.com/docs/errors/E1001 (unversioned).
+ * This middleware redirects those paths to the current default docs version
+ * (e.g., /docs/4.x/errors/e1001) so the content can be resolved.
+ *
+ * The error code is lowercased to match the content collection path.
+ */
+export default defineEventHandler((event) => {
+  const path = getRequestURL(event).pathname
+
+  // Match /docs/errors/... but NOT /docs/3.x/errors/... or /docs/4.x/errors/...
+  const match = path.match(/^\/docs\/errors\/(.+)$/)
+  if (match?.[1]) {
+    // TODO: update to /docs/5.x when Nuxt 5 is the default
+    return sendRedirect(event, `/docs/4.x/errors/${match[1].toLowerCase()}`, 302)
+  }
+})

server/routes/e/[code].get.ts

@@ -0,0 +1,24 @@
+/**
+ * Short URL handler for Nuxt error codes.
+ *
+ * Redirects /e/NUXT_E1001 → /docs/4.x/errors/e1001
+ * Redirects /e/NUXT_B1001 → /docs/4.x/errors/b1001
+ *
+ * The error code format is NUXT_ followed by E or B and 1-4 digits.
+ * The NUXT_ prefix is stripped, the code is lowercased, and the user
+ * is redirected to the current default docs version.
+ */
+export default defineEventHandler((event) => {
+  const code = getRouterParam(event, 'code')
+
+  // Validate: must be NUXT_ followed by E or B and 1-4 digits
+  if (!code || !/^NUXT_[EB]\d{1,4}$/i.test(code)) {
+    throw createError({ statusCode: 404, statusMessage: 'Not found' })
+  }
+
+  // Strip the NUXT_ prefix and lowercase → e1001 or b1001
+  const errorCode = code.replace('NUXT_', '').toLowerCase()
+
+  // TODO: update to /docs/5.x when Nuxt 5 is the default
+  return sendRedirect(event, `/docs/4.x/errors/${errorCode}`, 302)
+})