Next.js Integration: useLocale Hook Documentation for next-intlayer

This section offers detailed documentation on the useLocale hook tailored for Next.js applications within the next-intlayer library. It is designed to handle locale changes and routing efficiently.

Importing useLocale in Next.js

To utilize the useLocale hook in your Next.js application, import it as shown below:

import { useLocale } from "next-intlayer"; // Used for managing locales and routing in Next.js

Usage

Here’s how to implement the useLocale hook within a Next.js component:

"use client";

import type { FC } from "react";
import { Locales } from "intlayer";
import { useLocale } from "next-intlayer";

const LocaleSwitcher: FC = () => {
  const { locale, defaultLocale, availableLocales, setLocale } = useLocale();

  return (
    <div>
      <h1>Current Locale: {locale}</h1>
      <p>Default Locale: {defaultLocale}</p>
      <select value={locale} onChange={(e) => setLocale(e.target.value)}>
        {availableLocales.map((loc) => (
          <option key={loc} value={loc}>
            {loc}
          </option>
        ))}
      </select>
    </div>
  );
};

Parameters

The useLocale hook accepts the following parameters:

• onLocaleChange: A string that determines how the URL should be updated when the locale changes. It can be "replace", "push" or "none".

  Let's take an example:

  1. You are on /fr/home
  2. You navigate to /fr/about
  3. You change the locale to /es/about
  4. You click the browser's "back" button

  The behavior will differ based on the onLocaleChange value:

  • "replace" (default) : Replaces the current URL with the new localized URL, and set the cookie. -> The "back" button will go to /es/home
  • "push": Adds the new localized URL to browser history, and set the cookie. -> The "back" button will go to /fr/about
  • "none": Only updates the locale in the client context, and set the cookie, without changing the URL. -> The "back" button will go to /fr/home

  • (locale) => void: Set the cookie and trigger a custom function that will be called when the locale changes.

    The undefined option is the default behavior as we recommend to use the Link component to navigate to the new locale. Example:

    tsx

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    <Link href="/es/about" replace>  About</Link>

Return Values

When you invoke the useLocale hook, it returns an object containing the following properties:

• locale: The current locale as set in the React context.
• defaultLocale: The primary locale defined in the configuration.
• availableLocales: A list of all locales available as defined in the configuration.
• setLocale: A function to change the application's locale and update the URL accordingly. It takes care of prefix rules, whether to add the locale to the path or not based on configuration. Utilizes useRouter from next/navigation for navigation functions like push and refresh.
• pathWithoutLocale: A computed property that returns the path without the locale. It is useful for comparing URLs. For example, if the current locale is fr, and the url fr/my_path, the path without locale is /my_path. Utilizes usePathname from next/navigation to get the current path.

Conclusion

The useLocale hook from next-intlayer is a crucial tool for managing locales in Next.js applications. It offers an integrated approach to adapt your application for multiple locales by handling locale storage, state management, and URL modifications seamlessly.