fix(head): apply baseURL to head composable (#2912)

Co-authored-by: Bobbie Goede <bobbiegoede@gmail.com>

specs/issues/2911.spec.ts

@@ -0,0 +1,23 @@
+import { test, expect, describe } from 'vitest'
+import { fileURLToPath } from 'node:url'
+import { URL } from 'node:url'
+import { setup } from '../utils'
+import { renderPage } from '../helper'
+
+describe('#2911', async () => {
+  await setup({
+    rootDir: fileURLToPath(new URL(`../fixtures/basic`, import.meta.url)),
+    browser: true,
+    nuxtConfig: {
+      app: {
+        baseURL: '/base-path'
+      }
+    }
+  })
+
+  test('`useLocaleHead` uses Nuxt `app.baseURL` in meta tags', async () => {
+    const { page } = await renderPage('/base-path')
+
+    expect(await page.locator('head #i18n-alt-en').getAttribute('href')).toMatch(/\/base-path$/)
+  })
+})

src/runtime/routing/compatibles/head.ts

@@ -3,6 +3,7 @@ import { unref, useNuxtApp, useRuntimeConfig } from '#imports'
 import { getComposer, getLocale, getLocales, getNormalizedLocales } from '../utils'
 import { getRouteBaseName, localeRoute, switchLocalePath } from './routing'
 import { isArray, isObject } from '@intlify/shared'
+import { joinURL } from 'ufo'
 
 import type { I18nHeadMetaInfo, MetaAttrs, LocaleObject, I18nHeadOptions } from '#build/i18n.options.mjs'
 import type { CommonComposableOptions } from '../../utils'
@@ -72,8 +73,9 @@ export function localeHead(
 }
 
 function getBaseUrl() {
-  const i18n = getComposer(useNuxtApp().$i18n)
-  return unref(i18n.baseUrl)
+  const nuxtApp = useNuxtApp()
+  const i18n = getComposer(nuxtApp.$i18n)
+  return joinURL(unref(i18n.baseUrl), nuxtApp.$config.app.baseURL)
 }
 
 export function getHreflangLinks(
@@ -224,5 +226,5 @@ function hypenToUnderscore(str: string) {
 
 function toAbsoluteUrl(urlOrPath: string, baseUrl: string) {
   if (urlOrPath.match(/^https?:\/\//)) return urlOrPath
-  return baseUrl + urlOrPath
+  return joinURL(baseUrl, urlOrPath)
 }