fix: empty i18n options not loading vue-i18n config file (#3093)

package.json

@@ -84,9 +84,9 @@
     "@intlify/unplugin-vue-i18n": "^3.0.1",
     "@intlify/utils": "^0.12.0",
     "@miyaneee/rollup-plugin-json5": "^1.2.0",
-    "@nuxt/kit": "^3.12.4",
+    "@nuxt/kit": "^3.13.1",
     "@rollup/plugin-yaml": "^4.1.2",
-    "@vue/compiler-sfc": "^3.4.37",
+    "@vue/compiler-sfc": "^3.5.4",
     "debug": "^4.3.5",
     "defu": "^6.1.2",
     "estree-walker": "^3.0.3",
@@ -100,15 +100,15 @@
     "ufo": "^1.3.1",
     "unplugin": "^1.10.1",
     "vue-i18n": "^9.9.0",
-    "vue-router": "^4.4.0"
+    "vue-router": "^4.4.4"
   },
   "devDependencies": {
     "@babel/parser": "^7.24.7",
     "@babel/plugin-syntax-import-assertions": "^7.24.7",
     "@babel/types": "^7.24.7",
     "@eslint/js": "9.5.0",
     "@nuxt/module-builder": "^0.8.3",
-    "@nuxt/schema": "^3.12.4",
+    "@nuxt/schema": "^3.13.1",
     "@types/debug": "^4.1.9",
     "@types/eslint": "^8.56.6",
     "@unhead/vue": "^1.8.8",
@@ -128,10 +128,10 @@
     "lint-staged": "^15.2.7",
     "nitropack": "^2.9.6",
     "npm-run-all2": "^6.2.0",
-    "nuxt": "^3.12.4",
+    "nuxt": "^3.13.1",
     "ofetch": "^1.3.4",
-    "playwright": "^1.38.1",
     "pkg-pr-new": "^0.0.20",
+    "playwright": "^1.38.1",
     "prettier": "^3.3.2",
     "ts-essentials": "^9.4.2",
     "typescript": "^5.5.2",
@@ -140,7 +140,7 @@
     "undici": "^6.19.2",
     "unhead": "^1.8.8",
     "vitest": "^1.6.0",
-    "vue": "^3.4.37"
+    "vue": "^3.5.4"
   },
   "lint-staged": {
     "*.{json,md,yml}": [

specs/basic_usage.spec.ts

@@ -89,6 +89,8 @@ describe('basic usage', async () => {
         // @ts-ignore
         delete x.components[component].__file
       }
+      // @ts-ignore
+      delete x.mods
       return x
     })
     expect(localeRoute).toMatchInlineSnapshot(

specs/empty_options.spec.ts

@@ -0,0 +1,18 @@
+import { test, expect, describe } from 'vitest'
+import { fileURLToPath } from 'node:url'
+import { setup } from './utils'
+import { renderPage } from './helper'
+
+await setup({
+  rootDir: fileURLToPath(new URL(`./fixtures/empty_options`, import.meta.url)),
+  browser: true
+})
+
+describe('inline options are handled correctly', async () => {
+  test('inline options are handled correctly', async () => {
+    const { page } = await renderPage('/')
+
+    const text = await page.locator('#text-div').innerHTML()
+    expect(text).toMatchInlineSnapshot(`"Hi from @nuxtjs/i18n: from the en locale"`)
+  })
+})

specs/fixtures/empty_options/app.vue

@@ -0,0 +1,3 @@
+<template>
+  <div id="text-div">Hi from @nuxtjs/i18n: {{ $t('hello') }}</div>
+</template>

specs/fixtures/empty_options/i18n.config.ts

@@ -0,0 +1,9 @@
+export default defineI18nConfig(() => ({
+  legacy: false,
+  locale: 'en',
+  messages: {
+    en: {
+      hello: 'from the en locale'
+    }
+  }
+}))

specs/fixtures/empty_options/nuxt.config.ts

@@ -0,0 +1,5 @@
+// https://nuxt.com/docs/guide/directory-structure/nuxt.config
+export default defineNuxtConfig({
+  compatibilityDate: '2024-04-03',
+  modules: ['@nuxtjs/i18n']
+})

specs/fixtures/empty_options/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "nuxt3-test-empty-options",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "build": "nuxi build",
+    "dev": "nuxi dev",
+    "generate": "nuxi generate",
+    "preview": "nuxi preview"
+  },
+  "devDependencies": {
+    "@nuxtjs/i18n": "latest",
+    "nuxt": "latest"
+  }
+}

specs/fixtures/empty_options/tsconfig.json

@@ -0,0 +1,4 @@
+{
+  // https://nuxt.com/docs/guide/concepts/typescript
+  "extends": "./.nuxt/tsconfig.json"
+}

src/layers.ts

@@ -166,9 +166,7 @@ export async function resolveLayerVueI18nConfigInfo(options: NuxtI18nOptions) {
 
   const resolveArr = nuxt.options._layers.map(async layer => {
     const i18n = getLayerI18n(layer)
-    if (i18n == null) return undefined
-
-    const res = await resolveVueI18nConfigInfo(resolveI18nDir(layer, i18n, true), i18n.vueI18n)
+    const res = await resolveVueI18nConfigInfo(resolveI18nDir(layer, i18n || {}, true), i18n?.vueI18n)
 
     if (res == null && i18n?.vueI18n != null) {
       logger.warn(