feat(nuxt): add apps to nuxt build-time instance (#20637)

packages/nuxt/src/core/builder.ts

@@ -11,6 +11,8 @@ import { generateApp as _generateApp, createApp } from './app'
 
 export async function build (nuxt: Nuxt) {
   const app = createApp(nuxt)
+  nuxt.apps.default = app
+
   const generateApp = debounce(() => _generateApp(nuxt, app), undefined, { leading: true })
   await generateApp()
 

packages/nuxt/src/core/nuxt.ts

@@ -37,7 +37,8 @@ export function createNuxt (options: NuxtOptions): Nuxt {
     hook: hooks.hook,
     ready: () => initNuxt(nuxt),
     close: () => Promise.resolve(hooks.callHook('close', nuxt)),
-    vfs: {}
+    vfs: {},
+    apps: {}
   }
 
   return nuxt

packages/schema/src/types/nuxt.ts

@@ -23,6 +23,8 @@ export interface Nuxt {
   server?: any
 
   vfs: Record<string, string>
+
+  apps: Record<string, NuxtApp>
 }
 
 export interface NuxtTemplate<Options = Record<string, any>> {