feat(bridge): use useMeta in bridge projects

packages/bridge/package.json

@@ -20,6 +20,7 @@
     "@nuxt/nitro": "3.0.0",
     "@nuxt/postcss8": "^1.1.3",
     "@vue/composition-api": "^1.2.3",
+    "@vueuse/head": "^0.6.0",
     "acorn": "^8.5.0",
     "defu": "^5.0.0",
     "enhanced-resolve": "^5.8.3",

packages/bridge/src/app.ts

@@ -12,9 +12,12 @@ export function setupAppBridge (_options: any) {
   // Transpile runtime/
   nuxt.options.build.transpile.push(resolve(distDir, 'runtime'))
 
-  // Resolve to same vue2 path
-  nuxt.options.alias.vue = nuxt.options.alias.vue ||
-    resolveModule('vue/dist/vue.runtime.esm.js', { paths: nuxt.options.modulesDir })
+  // Alias vue to a vue3-compat version of vue2
+  nuxt.options.alias['#vue'] = nuxt.options.alias.vue || resolveModule('vue/dist/vue.runtime.esm.js', { paths: nuxt.options.modulesDir })
+  nuxt.options.alias['@vue/shared'] = 'vue'
+  nuxt.options.alias['@vue/reactivity'] = 'vue'
+  nuxt.options.alias.vue = resolve(distDir, 'runtime/vue.mjs')
+  nuxt.options.build.transpile.push('vue')
 
   // Deprecate various Nuxt options
   if (nuxt.options.globalName !== 'nuxt') {

packages/bridge/src/global-imports.ts

@@ -3,7 +3,6 @@ import globalImports from '../../nuxt3/src/global-imports/module'
 
 // TODO: implement these: https://github.com/nuxt/framework/issues/549
 const disabled = [
-  'useMeta',
   'useAsyncData',
   'asyncData'
 ]
@@ -17,6 +16,9 @@ const identifiers = {
     'useRouter',
     'useRuntimeConfig'
   ],
+  '#meta': [
+    'useMeta'
+  ],
   '@vue/composition-api': [
     // lifecycle
     'onActivated',

packages/bridge/src/meta.ts

@@ -0,0 +1,33 @@
+import { resolve } from 'pathe'
+import { addTemplate, useNuxt, installModule } from '@nuxt/kit'
+import metaModule from '../../nuxt3/src/meta/module'
+import { distDir } from './dirs'
+
+const checkDocsMsg = 'Please see https://v3.nuxtjs.org for more information.'
+const msgPrefix = '[bridge] [meta]'
+
+interface SetupMetaOptions {
+  needsExplicitEnable?: boolean
+}
+
+export const setupMeta = async (opts: SetupMetaOptions) => {
+  const nuxt = useNuxt()
+
+  if (opts.needsExplicitEnable) {
+    const metaPath = addTemplate({
+      filename: 'meta.mjs',
+      getContents: () => `export const useMeta = () => console.warn('${msgPrefix} To use \`useMeta\`, please set \`bridge.meta\` to \`true\` in your \`nuxt.config\`. ${checkDocsMsg}')`
+    })
+    nuxt.options.alias['#meta'] = metaPath.dst
+    return
+  }
+
+  if (nuxt.options.head && typeof nuxt.options.head === 'function') {
+    throw new TypeError(`${msgPrefix} The head() function in \`nuxt.config\` has been deprecated and in nuxt3 will need to be moved to \`app.vue\`. ${checkDocsMsg}`)
+  }
+
+  const runtimeDir = resolve(distDir, 'runtime/meta')
+  nuxt.options.alias['#meta'] = runtimeDir
+
+  await installModule(nuxt, metaModule)
+}

packages/bridge/src/module.ts

@@ -7,6 +7,7 @@ import { setupCAPIBridge } from './capi'
 import { setupBetterResolve } from './resolve'
 import { setupGlobalImports } from './global-imports'
 import { setupTypescript } from './typescript'
+import { setupMeta } from './meta'
 
 export default defineNuxtModule({
   name: 'nuxt-bridge',
@@ -18,6 +19,7 @@ export default defineNuxtModule({
     capi: {},
     globalImports: true,
     constraints: true,
+    meta: null,
     // TODO: Remove from 2.16
     postcss8: true,
     typescript: true,
@@ -66,5 +68,8 @@ export default defineNuxtModule({
         }
       })
     }
+    if (opts.meta !== false && opts.capi) {
+      await setupMeta({ needsExplicitEnable: opts.meta === null })
+    }
   }
 })

packages/bridge/src/runtime/app.plugin.mjs

@@ -1,14 +1,31 @@
+import Vue from 'vue'
 import { createHooks } from 'hookable/dist/index.mjs'
 import { setNuxtInstance } from '#app'
 
 export default (ctx, inject) => {
   const nuxt = {
+    app: {
+      component: Vue.component.bind(Vue),
+      config: {
+        globalProperties: {}
+      },
+      directive: Vue.directive.bind(Vue),
+      mixin: Vue.mixin.bind(Vue),
+      mount: () => {},
+      provide: inject,
+      unmount: () => {},
+      use (vuePlugin) {
+        vuePlugin.install(this)
+      },
+      version: Vue.version
+    },
     provide: inject,
     globalName: 'nuxt',
     payload: process.client ? ctx.nuxtState : ctx.ssrContext.nuxt,
     isHydrating: ctx.isHMR,
     legacyNuxt: ctx.app
   }
+
   nuxt.hooks = createHooks()
   nuxt.hook = nuxt.hooks.hook
   nuxt.callHook = nuxt.hooks.callHook
@@ -17,6 +34,10 @@ export default (ctx, inject) => {
     ctx.app.created = [ctx.app.created]
   }
 
+  if (process.server) {
+    nuxt.ssrContext = ctx.ssrContext
+  }
+
   ctx.app.created.push(function () {
     nuxt.legacyApp = this
   })

packages/bridge/src/runtime/meta

@@ -0,0 +1 @@
+../../../nuxt3/src/meta/runtime

packages/bridge/src/runtime/nitro-bridge.server.mjs

@@ -1,27 +1,49 @@
-export default ({ ssrContext }) => {
-  ssrContext.renderMeta = () => {
-    const meta = ssrContext.meta.inject({
-      isSSR: ssrContext.nuxt.serverRendered,
-      ln: process.env.NODE_ENV === 'development'
-    })
+const vueMetaRenderer = (nuxt) => {
+  const meta = nuxt.ssrContext.meta.inject({
+    isSSR: nuxt.ssrContext.nuxt.serverRendered,
+    ln: process.env.NODE_ENV === 'development'
+  })
 
-    return {
-      htmlAttrs: meta.htmlAttrs.text(),
-      headAttrs: meta.headAttrs.text(),
-      headTags:
+  return {
+    htmlAttrs: meta.htmlAttrs.text(),
+    headAttrs: meta.headAttrs.text(),
+    headTags:
         meta.title.text() + meta.base.text() +
         meta.meta.text() + meta.link.text() +
         meta.style.text() + meta.script.text() +
         meta.noscript.text(),
-      bodyAttrs: meta.bodyAttrs.text(),
-      bodyScriptsPrepend:
+    bodyAttrs: meta.bodyAttrs.text(),
+    bodyScriptsPrepend:
         meta.meta.text({ pbody: true }) + meta.link.text({ pbody: true }) +
         meta.style.text({ pbody: true }) + meta.script.text({ pbody: true }) +
         meta.noscript.text({ pbody: true }),
-      bodyScripts:
+    bodyScripts:
         meta.meta.text({ body: true }) + meta.link.text({ body: true }) +
         meta.style.text({ body: true }) + meta.script.text({ body: true }) +
         meta.noscript.text({ body: true })
-    }
   }
 }
+
+export default defineNuxtPlugin((nuxt) => {
+  const metaRenderers = [vueMetaRenderer]
+
+  nuxt.callHook('meta:register', metaRenderers)
+
+  nuxt.ssrContext.renderMeta = async () => {
+    const metadata = {
+      htmlAttrs: '',
+      headAttrs: '',
+      headTags: '',
+      bodyAttrs: '',
+      bodyScriptsPrepend: '',
+      bodyScripts: ''
+    }
+    for await (const renderer of metaRenderers) {
+      const result = await renderer(nuxt)
+      for (const key in result) {
+        metadata[key] += result[key]
+      }
+    }
+    return metadata
+  }
+})

packages/bridge/src/runtime/vue.mjs

@@ -0,0 +1,7 @@
+import Vue from '#vue'
+
+export * from '@vue/composition-api'
+
+export const isFunction = fn => fn instanceof Function
+
+export { Vue as default }

packages/bridge/types.d.ts

@@ -11,6 +11,7 @@ export interface BridgeConfig {
   swc: boolean
   resolve: boolean
   typescript: boolean
+  meta: boolean | null
 }
 
 // TODO: Also inherit from @nuxt/types.NuxtConfig for legacy type compat

packages/kit/src/config/schema/_app.ts

@@ -103,6 +103,22 @@ export default {
     script: []
   },
 
+  /**
+   * Set default configuration for `<head>` on every page.
+   *
+   * @version 3
+   */
+  meta: {
+    /** Each item in the array maps to a newly-created `<meta>` element, where object properties map to attributes. */
+    meta: [],
+    /** Each item in the array maps to a newly-created `<link>` element, where object properties map to attributes. */
+    link: [],
+    /** Each item in the array maps to a newly-created `<style>` element, where object properties map to attributes. */
+    style: [],
+    /** Each item in the array maps to a newly-created `<script>` element, where object properties map to attributes. */
+    script: []
+  },
+
   /**
    * Configuration for the Nuxt `fetch()` hook.
    * @version 2

packages/nuxt3/src/app/nuxt.ts

@@ -1,3 +1,4 @@
+/* eslint-disable no-use-before-define */
 import { getCurrentInstance, reactive } from 'vue'
 import type { App, VNode } from 'vue'
 import { createHooks, Hookable } from 'hookable'
@@ -21,6 +22,7 @@ export interface RuntimeNuxtHooks {
   'app:rendered': () => HookResult
   'page:start': (Component?: VNode) => HookResult
   'page:finish': (Component?: VNode) => HookResult
+  'meta:register': (metaRenderers: Array<(nuxt: NuxtApp) => NuxtMeta | Promise<NuxtMeta>>) => HookResult
 }
 
 export interface NuxtApp {

packages/nuxt3/src/meta/module.ts

@@ -1,5 +1,6 @@
 import { resolve } from 'pathe'
-import { addPlugin, addTemplate, defineNuxtModule } from '@nuxt/kit'
+import { addPlugin, addTemplate, defineNuxtModule, isNuxt3 } from '@nuxt/kit'
+import defu from 'defu'
 import { distDir } from '../dirs'
 import type { MetaObject } from './runtime'
 
@@ -10,7 +11,7 @@ export default defineNuxtModule({
     viewport: 'width=device-width, initial-scale=1'
   },
   setup (options, nuxt) {
-    const runtimeDir = resolve(distDir, 'meta/runtime')
+    const runtimeDir = nuxt.options.alias['#meta'] || resolve(distDir, 'meta/runtime')
 
     // Transpile @nuxt/meta and @vueuse/head
     nuxt.options.build.transpile.push(runtimeDir, '@vueuse/head')
@@ -19,17 +20,17 @@ export default defineNuxtModule({
     nuxt.options.alias['#meta'] = runtimeDir
 
     // Global meta
-    const globalMeta: MetaObject = {
+    const globalMeta: MetaObject = defu(nuxt.options.meta, {
       meta: [
         { charset: options.charset },
         { name: 'viewport', content: options.viewport }
       ]
-    }
+    })
 
     // Add global meta configuration
     addTemplate({
       filename: 'meta.config.mjs',
-      getContents: () => 'export default ' + JSON.stringify({ globalMeta })
+      getContents: () => 'export default ' + JSON.stringify({ globalMeta, mixinKey: isNuxt3() ? 'created' : 'setup' })
     })
 
     // Add generic plugin

packages/nuxt3/src/meta/runtime/plugin.ts

@@ -9,11 +9,12 @@ export default defineNuxtPlugin((nuxt) => {
   useMeta(metaConfig.globalMeta)
 
   nuxt.app.mixin({
-    created () {
+    [metaConfig.mixinKey] () {
       const instance = getCurrentInstance()
-      if (!instance?.type || !('head' in instance.type)) { return }
+      const options = instance?.type || /* nuxt2 */ instance?.proxy?.$options
+      if (!options || !('head' in options)) { return }
 
-      useMeta((instance.type as any).head)
+      useMeta(options.head)
     }
   })
 

test/fixtures/bridge/pages/index.vue

@@ -3,11 +3,17 @@
 </template>
 
 <script>
+import { useMeta } from '#meta'
+
 export default defineComponent({
   setup () {
+    useMeta({ meta: [{ name: 'description', content: 'This is a page to demo Nuxt Bridge.' }] })
     return {
       version: ref('2')
     }
+  },
+  head: {
+    title: 'Bridge test fixture'
   }
 })
 </script>

yarn.lock

@@ -1427,6 +1427,7 @@ __metadata:
     "@types/fs-extra": ^9.0.13
     "@types/node-fetch": ^3.0.2
     "@vue/composition-api": ^1.2.3
+    "@vueuse/head": ^0.6.0
     acorn: ^8.5.0
     defu: ^5.0.0
     enhanced-resolve: ^5.8.3