Documentation: getLocalizedPath Function in intlayer

Description

The getLocalizedPath function localizes a canonical path (internal application path): it resolves the custom rewrite rules, then applies the locale prefix of your routing mode. It is particularly useful for generating SEO-friendly URLs that vary by language.

It is the relative counterpart of getLocalizedUrl, for a relative input both return the same value. Unlike getLocalizedUrl, it never returns an absolute URL: the domains configuration is ignored, so a locale served from its own domain still yields a path. An absolute input is accepted, but its origin is dropped, only its path, query string and hash are kept.

Key Features:

• Supports dynamic route parameters using the [param] syntax.
• Resolves paths according to custom rewrite rules defined in your configuration.
• Applies the locale prefix of the configured routing mode (prefix-no-default, prefix-all, …).
• Automatically handles fallback to the canonical path if no rewrite rule is found for the specified locale.
• Narrows its return type: a literal path resolves to the localized string literal at compile time.

Function Signature

getLocalizedPath(
  canonicalPath: string,     // Required
  locale?: Locales,          // Optional
  options?: {                // Optional
    locales?: Locales[];
    defaultLocale?: Locales;
    mode?: 'prefix-no-default' | 'prefix-all' | 'no-prefix' | 'search-params';
    rewrite?: RoutingConfig['rewrite'];
  }
): string

Parameters

Required Parameters

• canonicalPath: string
  • Description: The internal application path (e.g., /about, /product/[id]).
  • Type: string
  • Required: Yes

Optional Parameters

• locale?: Locales

  • Description: The target locale for which the path should be localized.
  • Type: Locales
  • Default: The default locale of your project's configuration.

• options?: object

  • Description: Routing overrides. Every entry defaults to your project's configuration.

  • Type: object

  • options.locales?: Locales[]: supported locales. Default: configuration.internationalization.locales
  • options.defaultLocale?: Locales: the default locale. Default: configuration.internationalization.defaultLocale
  • options.mode?: 'prefix-no-default' | 'prefix-all' | 'no-prefix' | 'search-params': how the locale appears in the path. Default: configuration.routing.mode
  • options.rewrite?: RoutingConfig['rewrite']: custom rewrite rules. Default: configuration.routing.rewrite

Returns

• Type: string
• Description: The localized path for the specified locale.

The type is narrowed from the rewrite rules declared in your configuration, so the editor shows the resolved path rather than a bare string:

// Configuration: mode 'prefix-no-default', defaultLocale 'en',
//                { '/about': { fr: '/a-propos' }, '/product/[id]': { fr: '/produit/[id]' } }
const about = getLocalizedPath("/about", Locales.FRENCH);
//    ^? '/fr/a-propos'
const product = getLocalizedPath("/product/123", Locales.FRENCH);
//    ^? '/fr/produit/123'
const contact = getLocalizedPath("/contact", Locales.FRENCH);
//    ^? '/fr/contact'  (no rewrite rule matches, only the prefix is applied)
const home = getLocalizedPath("/", Locales.FRENCH);
//    ^? '/fr'

The same narrowing flows into getLocalizedUrl, which applies the rewrite rules before prefixing the locale.

Two cases stay widened to string, because they cannot be resolved at compile time:

• a path that is not a string literal (e.g. one built from a variable);
• a path matched by a rule using a multi-segment or optional parameter ([...slug], [[...slug]], :param?).

Example Usage

Basic Usage (With Configuration)

If you have configured custom rewrites in your intlayer.config.ts:

import { getLocalizedPath, Locales } from "intlayer";

// Configuration: mode 'prefix-no-default', defaultLocale 'en',
//                { '/about': { en: '/about', fr: '/a-propos' } }
getLocalizedPath("/about", Locales.FRENCH);
// Output: "/fr/a-propos"

getLocalizedPath("/about", Locales.ENGLISH);
// Output: "/about" (default locale, no prefix)

Usage with Dynamic Routes

import { getLocalizedPath, Locales } from "intlayer";

// Configuration: { '/product/[id]': { en: '/product/[id]', fr: '/produit/[id]' } }
getLocalizedPath("/product/123", Locales.FRENCH);
// Output: "/fr/produit/123"

Manual Rewrite Rules

You can also pass manual rewrite rules to the function:

import { getLocalizedPath, Locales } from "intlayer";

const manualRules = {
  "/contact": {
    en: "/contact-us",
    fr: "/contactez-nous",
  },
};

getLocalizedPath("/contact", Locales.FRENCH, { rewrite: manualRules });
// Output: "/fr/contactez-nous"

Omitting the Locale

When no locale is given, the path is localized for the configured default locale:

import { getLocalizedPath } from "intlayer";

// Configuration: defaultLocale = Locales.ENGLISH, { '/about': { en: '/about', fr: '/a-propos' } }
getLocalizedPath("/about");
// Output: "/about"

Related Functions