feat(nuxt, bridge): support titleTemplate, viewport and charset for useHead (#4221)

docs/content/2.guide/2.features/4.head-management.md

@@ -1,26 +1,29 @@
 # Head Management
 
-You can customize the meta tags for your site through several different ways:
+Out-of-the-box, Nuxt provides good default values for `charset` and `viewport` meta tags, but you can override these if you need to, as well as customizing other meta tags for your site in several different ways.
+
+:ReadMore{link="/api/configuration/nuxt.config#head"}
 
 ## `useHead` Composable
 
-Within your `setup` function, you can call `useHead` with an object of meta properties with keys corresponding to meta tags: `title`, `base`, `script`, `style`, `meta` and `link`, as well as `htmlAttrs` and `bodyAttrs`. Alternatively, you can pass a function returning the object for reactive metadata.
+Within your `setup` function, you can call `useHead` with an object of meta properties with keys corresponding to meta tags: `title`, `titleTemplate`, `base`, `script`, `style`, `meta` and `link`, as well as `htmlAttrs` and `bodyAttrs`. There are also two shorthand properties, `charset` and `viewport`, which set the corresponding meta tags. Alternatively, you can pass a function returning the object for reactive metadata.
 
 For example:
 
-```js
-export default {
-  setup () {
-    useHead({
+```vue
+<script setup>
+useHead({
+  titleTemplate: 'My App - %s', // or, title => `My App - ${title}`
+  viewport: 'width=device-width, initial-scale=1, maximum-scale=1',
+  charset: 'utf-8',
   meta: [
-        { name: 'viewport', content: 'width=device-width, initial-scale=1, maximum-scale=1' }
+    { name: 'description', content: 'My amazing site.' }
   ],
   bodyAttrs: {
     class: 'test'
   }
-    })
-  }
-}
+})
+</script>
 ```
 
 ::ReadMore{link="/api/composables/use-head"}
@@ -68,7 +71,7 @@ export default {
 
 You can use `definePageMeta` along with `useHead` to set metadata based on the current route.
 
-For example, to include the page title alongside your app name, first define your page title:
+For example, you can first set the current page title (this is extracted at build time via a macro, so it can't be set dynamically):
 
 ```vue{}[pages/some-page.vue]
 <script setup>
@@ -78,14 +81,14 @@ definePageMeta({
 </script>
 ```
 
-And then in your layout file:
+And then in your layout file you might use the route metadata you've previously set:
 
 ```vue{}[layouts/default.vue]
 <script setup>
 const route = useRoute()
 
 useHead({
-  title: computed(() => `App Name - ${route.meta.title}`)
+  meta: [{ name: 'og:title', content: `App Name - ${route.meta.title}` }]
 })
 </script>
 ```

docs/content/migration/4.meta.md

@@ -11,7 +11,7 @@ Nuxt 3 provides several different ways to manage your meta tags.
 2. Through the `useHead` [composable](/guide/features/head-management)
 3. Through [global meta components](/guide/features/head-management)
 
-You can customize `title`, `base`, `script`, `style`, `meta`, `link`, `htmlAttrs` and `bodyAttrs`.
+You can customize `title`, `titleTemplate`, `base`, `script`, `style`, `meta`, `link`, `htmlAttrs` and `bodyAttrs`.
 
 ::alert{icon=📦}
 Nuxt currently uses [`vueuse/head`](https://github.com/vueuse/head) to manage your meta tags, but implementation details may change.

examples/composables/use-head/app.vue

@@ -27,6 +27,7 @@
 export default {
   setup () {
     useHead({
+      titleTemplate: '%s - useHead example',
       bodyAttrs: {
         class: 'test'
       }

packages/nuxt3/src/head/module.ts

@@ -21,12 +21,11 @@ export default defineNuxtModule({
     // Add #head alias
     nuxt.options.alias['#head'] = runtimeDir
 
-    // Global meta
+    // Global meta -for Bridge, this is necessary to repeat here
+    // and in packages/schema/src/config/_app.ts
     const globalMeta: MetaObject = defu(nuxt.options.app.head, {
-      meta: [
-        { charset: options.charset },
-        { name: 'viewport', content: options.viewport }
-      ]
+      charset: options.charset,
+      viewport: options.viewport
     })
 
     // Add global meta configuration

packages/nuxt3/src/head/runtime/lib/vueuse-head.plugin.ts

@@ -1,5 +1,6 @@
 import { createHead, renderHeadToString } from '@vueuse/head'
-import { ref, watchEffect, onBeforeUnmount, getCurrentInstance } from 'vue'
+import { computed, ref, unref, watchEffect, onBeforeUnmount, getCurrentInstance, ComputedGetter } from 'vue'
+import defu from 'defu'
 import type { MetaObject } from '..'
 import { defineNuxtPlugin } from '#app'
 
@@ -14,9 +15,26 @@ export default defineNuxtPlugin((nuxtApp) => {
     headReady = true
   })
 
-  nuxtApp._useHead = (meta: MetaObject) => {
-    const headObj = ref(meta as any)
-    head.addHeadObjs(headObj)
+  const titleTemplate = ref<MetaObject['titleTemplate']>()
+
+  nuxtApp._useHead = (meta: MetaObject | ComputedGetter<MetaObject>) => {
+    titleTemplate.value = (unref(meta) as MetaObject).titleTemplate || titleTemplate.value
+
+    const headObj = computed(() => {
+      const overrides: MetaObject = { meta: [] }
+      const val = unref(meta) as MetaObject
+      if (titleTemplate.value && 'title' in val) {
+        overrides.title = typeof titleTemplate.value === 'function' ? titleTemplate.value(val.title) : titleTemplate.value.replace(/%s/g, val.title)
+      }
+      if (val.charset) {
+        overrides.meta!.push({ key: 'charset', charset: val.charset })
+      }
+      if (val.viewport) {
+        overrides.meta!.push({ name: 'viewport', content: val.viewport })
+      }
+      return defu(overrides, val)
+    })
+    head.addHeadObjs(headObj as any)
 
     if (process.server) { return }
 

packages/schema/src/config/_app.ts

@@ -102,6 +102,8 @@ export default {
     head: {
       $resolve: (val, get) => {
         return defu(val, get('meta'), {
+          charset: 'utf-8',
+          viewport: 'width=device-width, initial-scale=1',
           meta: [],
           link: [],
           style: [],

packages/schema/src/types/meta.ts

@@ -21,4 +21,6 @@ export interface MetaObject extends Record<string, any> {
   style?: Array<Record<string, any>>
   /** Each item in the array maps to a newly-created `<script>` element, where object properties map to attributes. */
   script?: Array<Record<string, any>>
+
+  titleTemplate?: string | ((title: string) => string)
 }

test/basic.test.ts

@@ -36,8 +36,6 @@ describe('pages', () => {
 
     // should render text
     expect(html).toContain('Hello Nuxt 3!')
-    // should render <Head> components
-    expect(html).toContain('<title>Basic fixture</title>')
     // should inject runtime config
     expect(html).toContain('RuntimeConfig | testConfig: 123')
     // composables auto import
@@ -119,12 +117,20 @@ describe('pages', () => {
 describe('head tags', () => {
   it('should render tags', async () => {
     const html = await $fetch('/head')
-    expect(html).toContain('<title>Using a dynamic component</title>')
+    expect(html).toContain('<title>Using a dynamic component - Fixture</title>')
     expect(html).not.toContain('<meta name="description" content="first">')
+    expect(html).toContain('<meta charset="utf-16">')
+    expect(html).not.toContain('<meta charset="utf-8">')
     expect(html).toContain('<meta name="description" content="overriding with an inline useHead call">')
     expect(html).toMatch(/<html[^>]*class="html-attrs-test"/)
     expect(html).toMatch(/<body[^>]*class="body-attrs-test"/)
     expect(html).toContain('script>console.log("works with useMeta too")</script>')
+
+    const index = await $fetch('/')
+    // should render charset by default
+    expect(index).toContain('<meta charset="utf-8">')
+    // should render <Head> components
+    expect(index).toContain('<title>Basic fixture - Fixture</title>')
   })
 })
 

test/fixtures/basic/pages/head.vue

@@ -5,7 +5,7 @@ useHead({
   },
   meta: [{ name: 'description', content: 'first' }]
 })
-useHead({ meta: [{ name: 'description', content: 'overriding with an inline useHead call' }] })
+useHead({ charset: 'utf-16', meta: [{ name: 'description', content: 'overriding with an inline useHead call' }] })
 useMeta({ script: [{ children: 'console.log("works with useMeta too")' }] })
 </script>
 

test/fixtures/basic/plugins/my-plugin.ts

@@ -1,4 +1,7 @@
 export default defineNuxtPlugin(() => {
+  useHead({
+    titleTemplate: '%s - Fixture'
+  })
   return {
     provide: {
       myPlugin: () => 'Injected by my-plugin'