@leanera/nuxt-i18n

Nuxt 3 module for internationalization with locale auto-imports & localized routing.

This module's intention is not to provide a full-blown solution for internationalization like @nuxtjs/i18n, but offer a lean, effective and lightweight set of tools to cover your needs without the bloat of a full-blown solution.

Key Features

• 🪡 Integration with @leanera/vue-i18n
• 🗜 Composable usage with useI18n
• 🪢 Auto-importable locale messages (JSON/YAML support)
• 💇‍♀️ Lazy-loading of translation messages
• 🛣 Automatic routes generation and custom paths

Setup

# pnpm
pnpm add -D @leanera/nuxt-i18n

# npm
npm i -D @leanera/nuxt-i18n

Basic Usage

📖 Check out the playground

Add @leanera/nuxt-i18n to your nuxt.confg.ts:

export default defineNuxtConfig({
  modules: ['@leanera/nuxt-i18n'],
})

For the most basic setup, add the locales and defaultLocales module options with a set of translation messages:

export default defineNuxtConfig({
  modules: ['@leanera/nuxt-i18n'],

  i18n: {
    locales: ['en', 'de'],
    defaultLocale: 'en',
    messages: {
      en: { welcome: 'Welcome' },
      de: { welcome: 'Willkommen' }
    }
  }
})

Use the globally available useI18n composable in your component's setup hook:

<script setup>
const { locale, t } = useI18n()
</script>

<template>
  <div>Language: {{ locale }}</div>
  <p>{{ t('welcome') }}</p>
</template>

Guide

Routing & Strategies

You can opt-in to override the Nuxt default routes with added locale prefixes to every URL by using one of the built-in routing strategies. By default, the generated routes stay untouched (no_prefix strategy).

For example, if your app supports two languages: German and English as the default language, and you have the following pages in your project:

└── pages/
    ├── about/
    │   └── index.vue
    └── index.vue

This would result in the following routes being generated for the prefix_except_default strategy:

[
  {
    path: '/',
    name: 'index___en',
    // ...
  },
  {
    path: '/de/',
    name: 'index___de',
    // ...
  },
  {
    path: '/about',
    name: 'about___en',
    // ...
  },
  {
    path: '/de/about',
    name: 'about___de',
    // ...
  }
]

ℹ️ Note: Routes for the English version don't have a prefix because it is the default language.

Available Strategies

There are 4 supported strategies in total that affect how the app's routes are generated.

no_prefix (default)

With this strategy, routes stay as they are generated by Nuxt. No locale prefix will be added. The locale can be changed without changing the URL.

prefix_except_default

Using this strategy, all of your routes will have a locale prefix added except for the default language.

prefix

With this strategy, all routes will have a locale prefix.

prefix_and_default

This strategy combines both previous strategies behaviours, meaning that you will get URLs with prefixes for every language, but URLs for the default language will also have a non-prefixed version. This could lead to duplicated content. You will have to handle, which URL is preferred when navigating in your app.

Configuration

A strategy may be set using the strategy module option. Make sure that you have a defaultLocale defined in any case.

export default defineNuxtConfig({
  i18n: {
    locales: ['en', 'de'],
    defaultLocale: 'en',
    strategy: 'prefix_except_default',
  },
})

Custom Route Paths

In some cases, you might want to translate URLs in addition to having them prefixed with the locale code. For example, you might want to have a route like /about in English and /ueber-uns in German. You can achieve this by defining a custom path for the route in the nuxt.config.ts file:

export default defineNuxtConfig({
  i18n: {
    locales: ['en', 'de', 'fr'],
    defaultLocale: 'en',
    pages: {
      about: {
        de: '/ueber-uns',
        fr: '/a-propos'
      }
    }
  }
})

ℹ️ Each key within the pages object should correspond to the relative file-based path (excluding the .vue file extension) of the route within your pages directory.

Customized route paths must start with a / and not include the locale prefix.

Auto-Importing & Lazy-Loading Translations

For apps that contain a lot of translated content, it is preferable not to bundle all the messages in the main bundle, but rather lazy-load only the language that the users selected. By defining a directory where translation files are located, locale messages can be dynamically imported when the app loads or when the user switches to another language.

However, you can also benefit from the advantages of auto-import without enabling dynamic imports.

How to enable file-based translations with or without lazy-loading:

• Set the langImports option to true.
• Enable dynamic imports by setting the lazy option to true.
• Optionally, configure the langDir option to a directory that contains your translation files. Defaults to locales.
• Make sure the locales option covers possible languages.

ℹ️ Translation files must be called the same as their locale. Currently, JSON, JSON5 and YAML are supported.

Example files structure:

├── locales/
│   ├── en.json
│   ├── es.json5
│   ├── fr.yaml
└── nuxt.config.js

Configuration example:

export default defineNuxtConfig({
  i18n: {
    locales: ['en', 'es', 'fr'],
    defaultLocale: 'en',
    langImports: true,
    lazy: true
  }
})

ℹ️ If you prefer to import file-based translations but don't want to dynamically import them, omit the lazy module option, as it defaults to false.

⚠️ The global route middleware to lazy-load translations when switching locales won't run when the no_prefix strategy is chosen. Use the useLazyLocaleSwitch composable for changing the language, it will load the corresponding translations beforehand.

Manual Translations

Instead of auto-importing (with or without lazy-loading), you can manually import your translations and merge them into the global locale messages object:

// Import from JSON or an ES module
import en from './locales/en.json'
import de from './locales/de.json'

export default defineNuxtConfig({
  i18n: {
    locales: ['en', 'de'],
    defaultLocale: 'en',
    messages: {
      en,
      de,
    },
  },
})

The locale messages defined above will be passed as the messages option when initializing @leanera/vue-i18n with createI18n().

API

Module Options

interface ModuleOptions {
  /**
   * List of locales supported by your app
   *
   * @remarks
   * Intended to be an array of string codes, e.g. `['en', 'fr']`
   *
   * @default []
   */
  locales?: string[]

  /**
   * The app's default locale
   *
   * @remarks
   * It's recommended to set this to some locale regardless of the chosen strategy, as it will be used as a fallback locale
   *
   * @default 'en'
   */
  defaultLocale?: string

  /**
   * Directory where your locale files are stored
   *
   * @remarks
   * Expected to be a relative path from the project root
   *
   * @default 'locales'
   */
  langDir?: string

  /**
   * Whether to enable locale auto-importing
   *
   * @remarks
   * When enabled, the module will automatically import all locale files from the `langDir` directory
   *
   * @default false
   */
  langImports?: boolean

  /**
   * Whether to lazy-load locale messages in the client
   *
   * @remarks
   * If enabled, locale messages will be loaded on demand when the user navigates to a route with a different locale
   *
   * This has no effect if the `langImports` option is disabled
   *
   * Note: When `strategy` is set to `no_prefix`, use the `useLazyLocaleSwitch` composable to ensure the translation messages are loaded before switching locales
   *
   * @default false
   */
  lazy?: boolean

  /**
   * The app's default messages
   *
   * @remarks
   * Can be omitted if auto-importing of locales is enabled
   *
   * @default {}
   */
  messages?: LocaleMessages

  /**
   * Routes strategy
   *
   * @remarks
   * Can be set to one of the following:
   *
   * - `no_prefix`: routes won't have a locale prefix
   * - `prefix_except_default`: locale prefix added for every locale except default
   * - `prefix`: locale prefix added for every locale
   * - `prefix_and_default`: locale prefix added for every locale and default
   *
   * @default 'no_prefix'
   */
  strategy?: Strategies

  /**
   * Customize the names of the paths for a specific locale
   *
   * @remarks
   * In some cases, you might want to translate URLs in addition to having them prefixed with the locale code
   *
   * @example
   * pages: {
   *   about: {
   *     en: '/about-us', // Accessible at `/en/about-us`
   *     fr: '/a-propos', // Accessible at `/fr/a-propos`
   *     es: '/sobre'     // Accessible at `/es/sobre`
   *   }
   * }
   * @default {}
   */
  pages?: CustomRoutePages

  /**
   * Custom route overrides for the generated routes
   *
   * @example
   * routeOverrides: {
   *   // Use `en` catch-all page as fallback for non-existing pages
   *   '/en/:id(.*)*': '/:id(.*)*'
   * }
   *
   * @default {}
   */
  routeOverrides?: Record<string, string>

  /**
   * Print verbose debug information to the console during development mode
   *
   * @remarks
   * For example the list of localized routes (if enabled)
   *
   * @default false
   */
  logs?: boolean
}

Composables

useI18n

Gives access to the current i18n instance.

function useI18n(): UseI18n

interface UseI18n {
  defaultLocale: string
  locale: ComputedRef<string>
  locales: readonly string[]
  messages: LocaleMessages
  t: (key: string, params?: Record<string, any>) => string
  setLocale: (locale: string) => void
  getLocale: () => string
}

useRouteLocale

Returns the current locale based on the route name. Preferred for strategies other than no_prefix.

Type Declarations

function useRouteLocale(): string

useLocalizedPath

Returns a translated path for a given route. Preferred when working with all routing strategies except no_prefix.

Type Declarations

function useLocalizedPath(
  path: string,
  locale: string,
): string

Example

const to = useLocalizedPath(useRoute().fullPath, 'de')
useRouter().push(to)

useLazyLocaleSwitch

Ensures to load the translation messages for the given locale before switching to it. Mostly needed for the no_prefix strategy.

Type Declarations

function useLazyLocaleSwitch(locale: string): Promise<void>

Example

await useLazyLocaleSwitch('en')

💻 Development

1. Clone this repository
2. Enable Corepack using corepack enable
3. Install dependencies using pnpm install
4. Run pnpm run dev:prepare
5. Start development server using pnpm run dev

Credits

• Kazuya Kawaguchi for his work on @intlify's vue-i18n-next, the next v8 alpha of nuxt-i18n as well as the i18n routing library vue-i18n-routing

License

MIT License © 2022-2023 Johann Schopplich & LeanERA GmbH