fix: support variable default export for defineI18nConfig (#2792)

* fix: support variable default export for `defineI18nConfig`

* test: add variable export `defineI18nConfig` test

specs/fixtures/issues/2094/app.vue

@@ -0,0 +1,5 @@
+<template>
+  <div>
+    <NuxtPage />
+  </div>
+</template>

specs/fixtures/issues/2094/i18n.config.ts

@@ -0,0 +1,13 @@
+const config = defineI18nConfig(() => {
+  return {
+    legacy: false,
+    locale: 'ja',
+    messages: {
+      ja: {
+        big: 'こんにちは,'.repeat(10)
+      }
+    }
+  }
+})
+
+export default config

specs/fixtures/issues/2094/nuxt.config.ts

@@ -0,0 +1,15 @@
+// https://nuxt.com/docs/api/configuration/nuxt-config
+export default defineNuxtConfig({
+  modules: ['@nuxtjs/i18n'],
+
+  i18n: {
+    defaultLocale: 'ja',
+    locales: [
+      {
+        code: 'ja',
+        iso: 'ja-JP',
+        name: 'Japanese'
+      }
+    ]
+  }
+})

specs/fixtures/issues/2094/package.json

@@ -0,0 +1,15 @@
+{
+  "name": "nuxt3-test-issues-2000",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "build": "nuxt build",
+    "dev": "nuxt dev",
+    "generate": "nuxt generate",
+    "start": "node .output/server/index.mjs"
+  },
+  "devDependencies": {
+    "@nuxtjs/i18n": "latest",
+    "nuxt": "latest"
+  }
+}

specs/fixtures/issues/2094/pages/index.vue

@@ -0,0 +1,9 @@
+<script setup lang="ts">
+import { useI18n } from 'vue-i18n'
+
+const { t } = useI18n()
+</script>
+
+<template>
+  <p id="render">{{ t('big') }}</p>
+</template>

specs/issues/2094.spec.ts

@@ -0,0 +1,17 @@
+import { test, describe, expect } from 'vitest'
+import { fileURLToPath } from 'node:url'
+import { setup } from '../utils'
+import { getText, renderPage } from '../helper'
+
+describe('#2094', async () => {
+  await setup({
+    rootDir: fileURLToPath(new URL(`../fixtures/issues/2094`, import.meta.url)),
+    browser: true
+  })
+
+  test('vue-i18n messages are loaded from config exported as variable', async () => {
+    const { page } = await renderPage('/')
+
+    expect(await getText(page, '#render')).toEqual('こんにちは,'.repeat(10))
+  })
+})

src/utils.ts

@@ -12,7 +12,7 @@ import { NUXT_I18N_MODULE_ID, TS_EXTENSIONS, EXECUTABLE_EXTENSIONS, NULL_HASH }
 
 import type { NuxtI18nOptions, LocaleInfo, VueI18nConfigPathInfo, LocaleType, LocaleFile, LocaleObject } from './types'
 import type { Nuxt, NuxtConfigLayer } from '@nuxt/schema'
-import type { File } from '@babel/types'
+import type { File, Identifier } from '@babel/types'
 
 export function formatMessage(message: string) {
   return `[${NUXT_I18N_MODULE_ID}]: ${message}`
@@ -150,27 +150,64 @@ function parseCode(code: string, path: string) {
 
 function scanProgram(program: File['program'] /*, calleeName: string*/) {
   let ret: false | 'object' | 'function' | 'arrow-function' = false
+  let variableDeclaration: Identifier | undefined
+
   for (const node of program.body) {
-    if (node.type === 'ExportDefaultDeclaration') {
-      if (node.declaration.type === 'ObjectExpression') {
-        ret = 'object'
+    if (node.type !== 'ExportDefaultDeclaration') continue
+
+    if (node.declaration.type === 'ObjectExpression') {
+      ret = 'object'
+      break
+    }
+
+    if (node.declaration.type === 'Identifier') {
+      variableDeclaration = node.declaration
+      break
+    }
+
+    if (node.declaration.type === 'CallExpression' && node.declaration.callee.type === 'Identifier') {
+      const [fnNode] = node.declaration.arguments
+      if (fnNode.type === 'FunctionExpression') {
+        ret = 'function'
         break
-      } else if (
-        node.declaration.type === 'CallExpression' &&
-        node.declaration.callee.type === 'Identifier' // &&
-        // node.declaration.callee.name === calleeName
-      ) {
-        const [fnNode] = node.declaration.arguments
-        if (fnNode.type === 'FunctionExpression') {
-          ret = 'function'
-          break
-        } else if (fnNode.type === 'ArrowFunctionExpression') {
-          ret = 'arrow-function'
+      }
+
+      if (fnNode.type === 'ArrowFunctionExpression') {
+        ret = 'arrow-function'
+        break
+      }
+    }
+  }
+
+  if (variableDeclaration) {
+    for (const node of program.body) {
+      if (node.type !== 'VariableDeclaration') continue
+      for (const decl of node.declarations) {
+        if (decl.type !== 'VariableDeclarator') continue
+        if (decl.init == null) continue
+        if ('name' in decl.id === false || decl.id.name !== variableDeclaration!.name) continue
+
+        if (decl.init.type === 'ObjectExpression') {
+          ret = 'object'
           break
         }
+
+        if (decl.init.type === 'CallExpression' && decl.init.callee.type === 'Identifier') {
+          const [fnNode] = decl.init.arguments
+          if (fnNode.type === 'FunctionExpression') {
+            ret = 'function'
+            break
+          }
+
+          if (fnNode.type === 'ArrowFunctionExpression') {
+            ret = 'arrow-function'
+            break
+          }
+        }
       }
     }
   }
+
   return ret
 }