feat: project relative layer locale resolution

specs/fixtures/basic_pages/nuxt.config.ts

@@ -11,14 +11,12 @@ export default defineNuxtConfig({
       {
         code: 'en',
         iso: 'en',
-        name: 'English',
-        file: 'en-US.json'
+        name: 'English'
       },
       {
         code: 'fr',
         iso: 'fr-FR',
-        name: 'Français',
-        file: 'fr-FR.json'
+        name: 'Français'
       }
     ],
     defaultLocale: 'en',

specs/fixtures/different_domains/nuxt.config.ts

@@ -28,7 +28,7 @@ export default defineNuxtConfig({
       {
         code: 'nl',
         iso: 'nl-NL',
-        file: 'nl.json',
+        // file: 'nl.json',
         domain: undefined,
         name: 'Nederlands'
       }

specs/fixtures/layers/layer-domain/nuxt.config.ts

@@ -5,7 +5,7 @@ export default defineNuxtConfig({
     differentDomains: true,
     defaultLocale: 'en',
     strategy: 'prefix_except_default',
-    // langDir: 'locales',
+    langDir: 'locales',
     locales: [
       {
         code: 'en',

specs/fixtures/layers/layer-pages/nuxt.config.ts

@@ -5,20 +5,17 @@ export default defineNuxtConfig({
       {
         code: 'en',
         iso: 'en-US',
-        name: 'English',
-        file: 'en-US.json'
+        name: 'English'
       },
       {
         code: 'fr',
         iso: 'fr-FR',
-        name: 'Français',
-        file: 'fr-FR.json'
+        name: 'Français'
       },
       {
         code: 'nl',
         iso: 'nl-NL',
-        name: 'Nederlands',
-        file: 'nl-NL.json'
+        name: 'Nederlands'
       }
     ]
   }

specs/utils/setup/index.ts

@@ -1,5 +1,5 @@
 import { createTestContext, setTestContext } from '../context'
-import { buildFixture, loadFixture, clearDir } from '../nuxt'
+import { buildFixture, loadFixture } from '../nuxt'
 import { startServer, stopServer } from '../server'
 import { createBrowser } from '../browser'
 import type { TestHooks, TestOptions } from '../types'
@@ -68,6 +68,16 @@ export function createTest(options: Partial<TestOptions>): TestHooks {
 }
 
 export async function setup(options: Partial<TestOptions> = {}) {
+  // Our layer support handles each layer individually (ignoring merged options)
+  // `nuxtConfig` overrides are not applied to `_layers` but passed to merged options
+  // `i18n.overrides` are applied at project layer to support overrides from tests
+
+  // @ts-ignore
+  if (options?.nuxtConfig?.i18n != null) {
+    // @ts-ignore
+    options.nuxtConfig.i18n = { ...options.nuxtConfig.i18n, overrides: options.nuxtConfig.i18n }
+  }
+
   const hooks = createTest(options)
 
   const setupFn = setupMaps[hooks.ctx.options.runner]

src/bundler.ts

@@ -19,16 +19,13 @@ export async function extendBundler(
   options: {
     nuxtOptions: Required<NuxtI18nOptions>
     hasLocaleFiles: boolean
-    langPath: string | null
   }
 ) {
   const { nuxtOptions, hasLocaleFiles } = options
   const langPaths = getLayerLangPaths(nuxt)
   debug('langPaths -', langPaths)
   const i18nModulePaths =
-    nuxt.options._layers[0].config.i18n?.i18nModules?.map(module =>
-      resolve(nuxt.options._layers[0].config.rootDir, module.langDir ?? '')
-    ) ?? []
+    nuxtOptions?.i18nModules?.map(module => resolve(nuxt.options._layers[0].config.rootDir, module.langDir ?? '')) ?? []
   debug('i18nModulePaths -', i18nModulePaths)
   const localePaths = [...langPaths, ...i18nModulePaths]
 

src/gen.ts

@@ -25,7 +25,6 @@ const debug = createDebug('@nuxtjs/i18n:gen')
 
 export function generateLoaderOptions(
   lazy: NonNullable<NuxtI18nOptions['lazy']>,
-  langDir: NuxtI18nOptions['langDir'],
   localesRelativeBase: string,
   vueI18nConfigPathInfo: VueI18nConfigPathInfo,
   vueI18nConfigPaths: VueI18nConfigPathInfo[],
@@ -68,10 +67,7 @@ export function generateLoaderOptions(
     const { root, dir, base, ext } = parsePath(relativePath)
     const key = makeImportKey(root, dir, base)
     if (!generatedImports.has(key)) {
-      let loadPath = relativePath
-      if (langDir) {
-        loadPath = resolveLocaleRelativePath(localesRelativeBase, langDir, relativePath)
-      }
+      const loadPath = resolveLocaleRelativePath(localesRelativeBase, relativePath)
       const assertFormat = ext.slice(1)
       const variableName = genSafeVariableName(`locale_${convertToImportId(key)}`)
       gen += `${genImport(
@@ -98,11 +94,9 @@ export function generateLoaderOptions(
   /**
    * Prepare locale files for synthetic or asynthetic
    */
-  if (langDir) {
-    for (const locale of localeInfo) {
-      if (!syncLocaleFiles.has(locale) && !asyncLocaleFiles.has(locale)) {
-        ;(lazy ? asyncLocaleFiles : syncLocaleFiles).add(locale)
-      }
+  for (const locale of localeInfo) {
+    if (!syncLocaleFiles.has(locale) && !asyncLocaleFiles.has(locale)) {
+      ;(lazy ? asyncLocaleFiles : syncLocaleFiles).add(locale)
     }
   }
 
@@ -236,7 +230,6 @@ export function generateLoaderOptions(
       }).join(`,`)}})\n`
     } else if (rootKey === 'localeInfo') {
       let codes = `export const localeMessages = {\n`
-      if (langDir) {
         for (const { code, file, files} of syncLocaleFiles) {
           const syncPaths = file ? [file] : files|| []
           codes += `  ${toCode(code)}: [${syncPaths.map(filepath => {
@@ -249,16 +242,15 @@ export function generateLoaderOptions(
           codes += `  ${toCode(localeInfo.code)}: [${convertToPairs(localeInfo).map(({ file, path, hash, type }) => {
             const { root, dir, base, ext } = parsePath(file)
             const key = makeImportKey(root, dir, base)
-            const loadPath = resolveLocaleRelativePath(localesRelativeBase, langDir, file)
+            const loadPath = resolveLocaleRelativePath(localesRelativeBase, file)
             return `{ key: ${toCode(loadPath)}, load: ${genDynamicImport(genImportSpecifier(loadPath, ext, path, type, { hash, query: { locale: localeInfo.code } }), { comment: `webpackChunkName: "lang_${normalizeWithUnderScore(key)}"` })} }`
           })}],\n`
         }
-      }
       codes += `}\n`
       return codes
-	  } else {
-	    return `export const ${rootKey} = ${toCode(rootValue)}\n`
-	  }
+    } else {
+      return `export const ${rootKey} = ${toCode(rootValue)}\n`
+    }
   }).join('\n')}`
 
   /**
@@ -314,15 +306,15 @@ function convertToImportId(file: string) {
     return IMPORT_ID_CACHES.get(file)
   }
 
-  const { name } = parsePath(file)
-  const id = normalizeWithUnderScore(name)
+  const { name, dir } = parsePath(file)
+  const id = normalizeWithUnderScore(`${dir}/${name}`)
   IMPORT_ID_CACHES.set(file, id)
 
   return id
 }
 
-function resolveLocaleRelativePath(relativeBase: string, langDir: string, file: string) {
-  return normalize(`${relativeBase}/${langDir}/${file}`)
+function resolveLocaleRelativePath(relativeBase: string, file: string) {
+  return normalize(`${relativeBase}/${file}`)
 }
 
 /* eslint-enable @typescript-eslint/no-explicit-any */

src/layers.ts

@@ -1,24 +1,79 @@
 import createDebug from 'debug'
-import { resolve } from 'pathe'
-import { getLayerI18n, getProjectPath, mergeConfigLocales, resolveVueI18nConfigInfo } from './utils'
+import {
+  getLayerI18n,
+  getProjectPath,
+  mergeConfigLocales,
+  resolveVueI18nConfigInfo,
+  LocaleConfig,
+  formatMessage
+} from './utils'
+
+import { useLogger } from '@nuxt/kit'
+import { isAbsolute, resolve } from 'pathe'
+import { isString } from '@intlify/shared'
+import { NUXT_I18N_MODULE_ID } from './constants'
 
 import type { Nuxt } from '@nuxt/schema'
-import type { LocaleObject } from 'vue-i18n-routing'
 import type { NuxtI18nOptions } from './types'
 
 const debug = createDebug('@nuxtjs/i18n:layers')
 
-export const applyLayerOptions = (options: NuxtI18nOptions, nuxt: Nuxt) => {
+export const checkLayerOptions = (options: NuxtI18nOptions, nuxt: Nuxt) => {
+  const logger = useLogger(NUXT_I18N_MODULE_ID)
   const project = nuxt.options._layers[0]
   const layers = nuxt.options._layers
 
-  // No layers to merge
-  if (layers.length === 1) return
+  for (const layer of layers) {
+    const layerI18n = getLayerI18n(layer)
+    if (layerI18n == null) continue
+
+    const configLocation = project.config.rootDir === layer.config.rootDir ? 'project layer' : 'extended layer'
+    const layerHint = `In ${configLocation} (\`${resolve(project.config.rootDir, layer.configFile)}\`) -`
+
+    try {
+      // check `lazy` and `langDir` option
+      if (layerI18n.lazy && !layerI18n.langDir) {
+        throw new Error('When using the `lazy`option you must also set the `langDir` option.')
+      }
+
+      // check `langDir` option
+      if (layerI18n.langDir) {
+        const locales = layerI18n.locales || []
+        if (!locales.length || locales.some(locale => isString(locale))) {
+          throw new Error('When using the `langDir` option the `locales` must be a list of objects.')
+        }
+
+        if (isString(layerI18n.langDir) && isAbsolute(layerI18n.langDir)) {
+          logger.warn(
+            `${layerHint} \`langdir\` is set to an absolute path (\`${layerI18n.langDir}\`) but should be set a path relative to \`srcDir\` (\`${layer.config.srcDir}\`). ` +
+              `Absolute paths will not work in production, see https://v8.i18n.nuxtjs.org/options/lazy#langdir for more details.`
+          )
+        }
+
+        for (const locale of locales) {
+          if (isString(locale) || !(locale.file || locale.files)) {
+            throw new Error(
+              'All locales must have the `file` or `files` property set when using `langDir`.\n' +
+                `Found none in:\n${JSON.stringify(locale, null, 2)}.`
+            )
+          }
+        }
+      }
+    } catch (err) {
+      if (!(err instanceof Error)) throw err
+      throw new Error(formatMessage(`${layerHint} ${err.message}`))
+    }
+  }
+}
+
+export const applyLayerOptions = (options: NuxtI18nOptions, nuxt: Nuxt) => {
+  const project = nuxt.options._layers[0]
+  const layers = nuxt.options._layers
 
   const resolvedLayerPaths = layers.map(l => resolve(project.config.rootDir, l.config.rootDir))
   debug('using layers at paths', resolvedLayerPaths)
 
-  const mergedLocales = mergeLayerLocales(nuxt)
+  const mergedLocales = mergeLayerLocales(options, nuxt)
   debug('merged locales', mergedLocales)
 
   options.locales = mergedLocales
@@ -38,94 +93,27 @@ export const mergeLayerPages = (analyzer: (pathOverride: string) => void, nuxt:
   }
 }
 
-export const mergeLayerLocales = (nuxt: Nuxt) => {
-  const projectLayer = nuxt.options._layers[0]
-  const projectI18n = getLayerI18n(projectLayer)
-
-  if (projectI18n == null) {
-    debug('project layer `i18n` configuration is required')
-    return []
-  }
-  debug('project layer `lazy` option', projectI18n.lazy)
+export const mergeLayerLocales = (options: NuxtI18nOptions, nuxt: Nuxt) => {
+  debug('project layer `lazy` option', options.lazy)
+  const projectLangDir = getProjectPath(nuxt, nuxt.options.srcDir)
+  options.locales ??= []
 
-  /**
-   * Merge locales when `lazy: false`
-   */
-  const mergeSimpleLocales = () => {
-    if (projectI18n.locales == null) return []
-
-    const firstI18nLayer = nuxt.options._layers.find(layer => {
+  const configs: LocaleConfig[] = nuxt.options._layers
+    .filter(layer => {
       const i18n = getLayerI18n(layer)
-      return i18n?.locales && i18n?.locales?.length > 0
+      return i18n?.locales != null
     })
-    if (firstI18nLayer == null) return []
-
-    const localeType = typeof getLayerI18n(firstI18nLayer)?.locales?.at(0)
-    const isStringLocales = (val: unknown): val is string[] => localeType === 'string'
-
-    const mergedLocales: string[] | LocaleObject[] = []
-
-    /*
-      Layers need to be reversed to ensure that the original first layer (project)
-      has the highest priority in merging (because in the reversed array it gets merged last)
-    */
-    const reversedLayers = [...nuxt.options._layers].reverse()
-    for (const layer of reversedLayers) {
+    .map(layer => {
       const i18n = getLayerI18n(layer)
-      debug('layer.config.i18n.locales', i18n?.locales)
-      if (i18n?.locales == null) continue
-
-      for (const locale of i18n.locales) {
-        if (isStringLocales(mergedLocales)) {
-          if (typeof locale !== 'string') continue
-          if (mergedLocales.includes(locale)) continue
-
-          mergedLocales.push(locale)
-          continue
-        }
-
-        if (typeof locale === 'string') continue
-        const localeEntry = mergedLocales.find(x => x.code === locale.code)
-
-        if (localeEntry == null) {
-          mergedLocales.push(locale)
-        } else {
-          Object.assign(localeEntry, locale, localeEntry)
-        }
+      return {
+        ...i18n,
+        // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+        langDir: resolve(layer.config.srcDir, i18n?.langDir ?? layer.config.srcDir),
+        projectLangDir
       }
-    }
-
-    return mergedLocales
-  }
-
-  const mergeLazyLocales = () => {
-    if (projectI18n.langDir == null) {
-      debug('project layer `i18n.langDir` is required')
-      return []
-    }
-
-    const projectLangDir = getProjectPath(nuxt, projectI18n.langDir)
-    debug('project path', getProjectPath(nuxt))
-
-    const configs = nuxt.options._layers
-      .filter(layer => {
-        const i18n = getLayerI18n(layer)
-        return i18n?.locales != null && i18n?.langDir != null
-      })
-      .map(layer => {
-        const i18n = getLayerI18n(layer)
-        return {
-          ...i18n,
-          // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
-          langDir: resolve(layer.config.rootDir, i18n!.langDir!),
-          projectLangDir
-        }
-      })
-
-    return mergeConfigLocales(configs)
-  }
+    })
 
-  return projectI18n.lazy ? mergeLazyLocales() : mergeSimpleLocales()
+  return mergeConfigLocales(configs)
 }
 
 /**