Documentation: getLocalizedUrl Function in intlayer

Description

The getLocalizedUrl function generates a localised URL by prefixing the given URL with the specified locale. It handles both absolute and relative URLs, ensuring that the correct locale prefix is applied based on the configuration.

Key Features:

• Only 2 parameters are required: url and currentLocale
• Optional options object with locales, defaultLocale, and mode
• Uses your project's internationalisation configuration as defaults
• Can be used with minimal parameters for simple cases or fully customised for complex scenarios
• Supports multiple routing modes: prefix-no-default, prefix-all, no-prefix, and search-params

Function Signature

getLocalizedUrl(  url: string,                   // Required  currentLocale: Locales,        // Required  options?: {                    // Optional    locales?: Locales[];    defaultLocale?: Locales;    mode?: 'prefix-no-default' | 'prefix-all' | 'no-prefix' | 'search-params';  }): string

Parameters

Description

The getLocalizedUrl function generates a localised URL by prefixing the given URL with the specified locale. It handles both absolute and relative URLs, ensuring that the correct locale prefix is applied based on the configuration.

Parameters

• url: string

  • Description: The original URL string to be prefixed with a locale.
  • Type: string

• currentLocale: Locales

  • Description: The current locale for which the URL is being localised.
  • Type: Locales

• locales: Locales[]

  • Description: Optional array of supported locales. By default, the configured locales in the project are provided.
  • Type: Locales[]
  • Default: Project Configuration

• defaultLocale: Locales

  • Description: The default locale for the application. By default, the configured default locale in the project is provided.
  • Type: Locales
  • Default: Project Configuration

• prefixDefault: boolean

  • Description: Whether to prefix the URL for the default locale. By default, the configured value in the project is provided.
  • Type: boolean
  • Default: Project Configuration

Returns

• Type: string
• Description: The localised URL for the specified locale.

Example Usage

Basic Usage (Only Required Parameters)

When you have configured your project with internationalisation settings, you can use the function with just the required parameters:

import { getLocalizedUrl, Locales } from "intlayer";

// Uses your project's configuration for locales, defaultLocale, and mode
getLocalizedUrl("/about", Locales.FRENCH);
// Output: "/fr/about" (assuming French is supported and mode is 'prefix-no-default')

getLocalizedUrl("/about", Locales.ENGLISH);
// Output: "/about" or "/en/about" (depending on your mode setting)

Advanced Usage (With Optional Parameters)

You can override the default configuration by providing the optional options parameter:

Relative URLs

import { getLocalizedUrl, Locales } from "intlayer";

getLocalizedUrl(
  "/about",
  Locales.FRENCH,
  [Locales.ENGLISH, Locales.FRENCH],
  Locales.ENGLISH,
  false
);

// Output: "/fr/about" for the French locale
// Output: "/about" for the default (English) locale

Partial Configuration Override

You can also provide only some of the optional parameters. The function will use your project configuration for any parameters you don't specify:

import { getLocalizedUrl, Locales } from "intlayer";// Only override the locales, use project config for defaultLocale and modegetLocalizedUrl("/about", Locales.SPANISH, {  locales: [Locales.ENGLISH, Locales.FRENCH, Locales.SPANISH],});// Only override mode, use project config for locales and defaultLocalegetLocalizedUrl("/about", Locales.ENGLISH, {  mode: "prefix-all", // Force prefix for all locales including default});// Override multiple optionsgetLocalizedUrl("/about", Locales.FRENCH, {  defaultLocale: Locales.ENGLISH,  mode: "search-params", // Use query parameters: /about?locale=fr});

Absolute URLs

getLocalizedUrl(  "https://example.com/about",  Locales.FRENCH, // Current Locale  [Locales.ENGLISH, Locales.FRENCH], // Supported Locales  Locales.ENGLISH, // Default Locale  false // Prefix Default Locale); // Output: "https://example.com/fr/about" for the FrenchgetLocalizedUrl(  "https://example.com/about",  Locales.ENGLISH, // Current Locale  [Locales.ENGLISH, Locales.FRENCH], // Supported Locales  Locales.ENGLISH, // Default Locale  false // Prefix Default Locale); // Output: "https://example.com/about" for the EnglishgetLocalizedUrl(  "https://example.com/about",  Locales.ENGLISH, // Current Locale  [Locales.ENGLISH, Locales.FRENCH], // Supported Locales  Locales.ENGLISH, // Default Locale  true // Prefix Default Locale); // Output: "https://example.com/en/about" for the English

Unsupported Locale

getLocalizedUrl(  "/about",  Locales.ITALIAN, // Current Locale  [Locales.ENGLISH, Locales.FRENCH], // Supported Locales  Locales.ENGLISH // Default Locale); // Output: "/about" (no prefix applied for unsupported locale)

Edge Cases

• No Locale Segment:

  • If the URL does not contain any locale segment, the function safely prefixes the appropriate locale.

• Default Locale:

  • When prefixDefault is false, the function does not prefix the URL for the default locale.

• Unsupported Locales:

  • For locales not listed in locales, the function does not apply any prefix.

Usage in Applications

In a multilingual application, configuring the internationalisation settings with locales and defaultLocale is critical for ensuring the correct language is displayed. Below is an example of how getLocalizedUrl can be used in an application setup:

import { Locales, type IntlayerConfig } from "intlayer";

// Configuration for supported locales and default locale
export default {
  internationalization: {
    locales: [Locales.ENGLISH, Locales.FRENCH, Locales.SPANISH],
    defaultLocale: Locales.ENGLISH,
  },
} satisfies IntlayerConfig;

export default config;

The above configuration ensures that the application recognises ENGLISH, FRENCH, and SPANISH as supported languages and uses ENGLISH as the fallback language.

Using this configuration, the getLocalizedUrl function can dynamically generate localised URLs based on the user's language preference:

getLocalizedUrl("/about", Locales.FRENCH); // Output: "/fr/about"getLocalizedUrl("/about", Locales.SPANISH); // Output: "/es/about"getLocalizedUrl("/about", Locales.ENGLISH); // Output: "/about"

By integrating getLocalizedUrl, developers can maintain consistent URL structures across multiple languages, enhancing both user experience and SEO.