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    Creation:2025-07-27Last update:2025-07-27

    Locale Mapper

    The Locale Mapper is a powerful utility that helps you work with internationalisation data in your Intlayer application. It provides three main functions to transform and organise locale-specific data: localeMap, localeFlatMap, and localeRecord.

    How Locale Mapper Works

    The Locale Mapper operates on a LocaleData object that contains all the necessary information about a locale:

    typescript
    type LocaleData = {  locale: LocalesValues; // Current locale code (e.g., 'en', 'fr')  defaultLocale: LocalesValues; // Default locale code  isDefault: boolean; // Whether this is the default locale  locales: LocalesValues[]; // Array of all available locales  urlPrefix: string; // URL prefix for this locale (e.g., '/fr' or '')};

    The mapper functions automatically generate this data for each locale in your configuration, taking into account:

    • Your configured list of locales
    • The default locale setting
    • Whether the default locale should be prefixed in URLs

    Core Functions

    localeMap

    Transforms each locale into a single object using a mapper function.

    typescript
    localeMap<T>(  mapper: (locale: LocaleData) => T,  locales?: LocalesValues[],  defaultLocale?: LocalesValues,  prefixDefault?: boolean): T[]

    Example: Creating route objects

    typescript
    import { localeMap } from "intlayer";const routes = localeMap((localizedData) => ({  path: localizedData.urlPrefix,  name: localizedData.locale,  isDefault: localizedData.isDefault,  locales: localizedData.locales,  defaultLocale: localizedData.defaultLocale,}));// Result:// [//   { path: '/', name: 'en', isDefault: true, locales: ['en', 'fr', 'es'], defaultLocale: 'en' },//   { path: '/fr', name: 'fr', isDefault: false, locales: ['en', 'fr', 'es'], defaultLocale: 'en' },//   { path: '/es', name: 'es', isDefault: false, locales: ['en', 'fr', 'es'], defaultLocale: 'en' }// ]

    localeFlatMap

    Similar to localeMap, but the mapper function returns an array of objects that gets flattened into a single array.

    typescript
    localeFlatMap<T>(  mapper: (locale: LocaleData) => T[],  locales?: LocalesValues[],  defaultLocale?: LocalesValues,  prefixDefault?: boolean): T[]

    Example: Creating multiple routes per locale

    typescript
    import { localeFlatMap } from "intlayer";const routes = localeFlatMap((localizedData) => [  {    path: localizedData.urlPrefix,    name: localizedData.locale,    isDefault: localizedData.isDefault,  },  {    path: `${localizedData.urlPrefix}/about`,    name: `${localizedData.locale}-about`,    isDefault: localizedData.isDefault,  },]);// Result:// [//   { path: '/', name: 'en', isDefault: true },//   { path: '/about', name: 'en-about', isDefault: true },//   { path: '/fr', name: 'fr', isDefault: false },//   { path: '/fr/about', name: 'fr-about', isDefault: false },//   { path: '/es', name: 'es', isDefault: false },//   { path: '/es/about', name: 'es-about', isDefault: false }// ]

    localeRecord

    Creates a record object where each locale is a key mapping to a value transformed by the mapper function.

    typescript
    localeRecord<T>(  mapper: (locale: LocaleData) => T,  locales?: Locales[],  defaultLocale?: Locales,  prefixDefault?: boolean): Record<Locales, T>

    Example: Loading translation files

    typescript
    import { localeRecord } from "intlayer";const translations = localeRecord(({ locale }) =>  require(`./translations/${locale}.json`));// Result:// {//   en: { welcome: 'Welcome', hello: 'Hello' },//   fr: { welcome: 'Bienvenue', hello: 'Bonjour' },//   es: { welcome: 'Bienvenido', hello: 'Hola' }// }

    Setting Up Locale Mapper

    The Locale Mapper automatically uses your Intlayer configuration, but you can override the defaults by passing parameters:

    Using Default Configuration

    typescript
    import { localeMap } from "intlayer";// Uses configuration from intlayer.config.tsconst routes = localeMap((data) => ({  path: data.urlPrefix,  locale: data.locale,}));

    Overriding Configuration

    typescript
    import { localeMap } from "intlayer";// Override locales and default localeconst customRoutes = localeMap(  (data) => ({ path: data.urlPrefix, locale: data.locale }),  ["en", "fr", "de"], // Custom locales  "en", // Custom default locale  true // Prefix default locale in URLs);

    Advanced Usage Examples

    Creating Navigation Menus

    typescript
    import { localeMap } from "intlayer";const navigationItems = localeMap((data) => ({  label: data.locale.toUpperCase(),  href: data.urlPrefix || "/",  isActive: data.isDefault,  flag: `/flags/${data.locale}.svg`,}));

    Generating Sitemap Data

    typescript
    import { localeFlatMap } from "intlayer";const sitemapUrls = localeFlatMap((data) => [  {    url: `${data.urlPrefix}/`,    lastmod: new Date().toISOString(),    changefreq: "daily",    priority: data.isDefault ? 1.0 : 0.8,  },  {    url: `${data.urlPrefix}/about`,    lastmod: new Date().toISOString(),    changefreq: "monthly",    priority: data.isDefault ? 0.8 : 0.6,  },]);

    Dynamic Translation Loading

    typescript
    import { localeRecord } from "intlayer";const translationModules = localeRecord(({ locale }) => ({  messages: import(`./locales/${locale}/messages.json`),  validation: import(`./locales/${locale}/validation.json`),  metadata: {    locale,    direction: ["ar", "he", "fa"].includes(locale) ? "rtl" : "ltr",  },}));

    Configuration Integration

    The Locale Mapper seamlessly integrates with your Intlayer configuration:

    • Locales: Automatically uses configuration.internationalization.locales
    • Default Locale: Uses configuration.internationalization.defaultLocale
    • URL Prefixing: Respects configuration.middleware.prefixDefault

    This ensures consistency across your application and reduces configuration duplication.

    Doc History

    Version Date Changes
    5.7.2 2025-07-27 Add locale mapper documentation
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