Getting Started with Intlayer and Next.js

Setting up Intlayer in a Next.js application is straightforward:

Step 1: Install Dependencies

Install the necessary packages using npm:

npm install intlayer next-intlayer

yarn add intlayer next-intlayer

pnpm add intlayer next-intlayer

Step 2: Configure Your Project

Create a config file to configure the languages of your application:

// intlayer.config.ts

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

const config: IntlayerConfig = {
  internationalization: {
    locales: [
      Locales.ENGLISH,
      Locales.FRENCH,
      Locales.SPANISH,
      // Your other locales
    ],
    defaultLocale: Locales.ENGLISH,
  },
};

export default config;

To see all available parameters, refer to the configuration documentation here.

Step 3: Integrate Intlayer in Your Next.js Configuration

Configure your Next.js setup to use Intlayer:

// next.config.mjs
import { withIntlayer } from "next-intlayer/server";

/** @type {import('next').NextConfig} */
const nextConfig = {};

export default withIntlayer(nextConfig);

Step 4: Configure Middleware for Locale Detection

Set up middleware to detect the user's preferred locale:

// src/middleware.ts
export { intlayerMiddleware as middleware } from "next-intlayer/middleware";

export const config = {
  matcher: "/((?!api|static|.*\\..*|_next).*)",
};

Step 5: Define Dynamic Locale Routes

Implement dynamic routing for localized content:

Change src/app/page.ts to src/app/[locale]/page.ts

Then, implement the generateStaticParams function in your application Layout.

// src/app/layout.tsx

import type { ReactNode } from "react";
import "./globals.css";

export { generateStaticParams } from "next-intlayer"; // Line to insert

const RootLayout = ({
  children,
}: Readonly<{
  children: ReactNode;
}>) => children;

export default RootLayout;

Then add a new layout in your [locale] directory:

// src/app/[locale]/layout.tsx

import { NextLayoutIntlayer } from "next-intlayer";
import { Inter } from "next/font/google";
import { getHTMLTextDir } from "intlayer";

const inter = Inter({ subsets: ["latin"] });

const LocaleLayout: NextLayoutIntlayer = ({ children, params: { locale } }) => (
  <html lang={locale} dir={getHTMLTextDir(locale)}>
    <body className={inter.className}>{children}</body>
  </html>
);

export default LocaleLayout;

Step 6: Declare Your Content

Create and manage your content dictionaries:

// src/app/[locale]/page.content.ts
import { t, type DeclarationContent } from "intlayer";

const pageContent = {
  key: "page",
  content: {
    getStarted: {
      main: t({
        en: "Get started by editing",
        fr: "Commencez par éditer",
        es: "Comience por editar",
      }),
      pageLink: "src/app/page.tsx",
    },
  },
} satisfies DeclarationContent;

export default pageContent;

See how to declare your Intlayer declaration files.

Step 7: Utilize Content in Your Code

Access your content dictionaries throughout your application:

// src/app/[locale]/page.ts

import { ClientComponentExample } from "@component/components/ClientComponentExample";
import { LocaleSwitcher } from "@component/components/LangSwitcherDropDown";
import { NestedServerComponentExample } from "@component/components/NestedServerComponentExample";
import { ServerComponentExample } from "@component/components/ServerComponentExample";
import { type NextPageIntlayer, IntlayerClientProvider } from "next-intlayer";
import { IntlayerServerProvider, useIntlayer } from "next-intlayer/server";

const Page: NextPageIntlayer = ({ params: { locale } }) => {
  const content = useIntlayer("page", locale);

  return (
    <>
      <p>
        {content.getStarted.main}
        <code>{content.getStarted.pageLink}</code>
      </p>
      {/**
       *   IntlayerServerProvider is used to provide the locale to the server children
       *   Don't work if set in the layout
       */}
      <IntlayerServerProvider locale={locale}>
        <ServerComponentExample />
      </IntlayerServerProvider>
      {/**
       *   IntlayerClientProvider is used to provide the locale to the client children
       *   Can be set in any parent component, including the layout
       */}
      <IntlayerClientProvider locale={locale}>
        <ClientComponentExample />
      </IntlayerClientProvider>
    </>
  );
};

export default Page;

// src/components/ClientComponentExample.tsx

"use client";

import { useIntlayer } from "next-intlayer";

export const ClientComponentExample = () => {
  const content = useIntlayer("client-component-example"); // Create related content declaration

  return (
    <div>
      <h2>{content.title} </h2>
      <p>{content.content}</p>
    </div>
  );
};

// src/components/ServerComponentExample.tsx

import { useIntlayer } from "next-intlayer/server";

export const ServerComponentExample = () => {
  const content = useIntlayer("server-component-example"); // Create related content declaration

  return (
    <div>
      <h2>{content.title} </h2>
      <p>{content.content}</p>
    </div>
  );
};

Note: If you want to use your content in a string attribute, such as alt, title, href, aria-label, etc., you must call the value of the function, like:
<img src={content.image.src.value} alt={content.image.value} />

For more detailed usage of intlayer into Client, or Server component, see the nextJS example here.

(Optional) Step 8: Internationalization of your metadata

In the case you want to internationalize your metadata, such as the title of your page, you can use the generateMetadata function provided by NextJS. Inside the function use the getTranslationContent function to translate your metadata.

// src/app/[locale]/layout.tsx or src/app/[locale]/page.tsx

import { type IConfigLocales, getTranslationContent } from 'intlayer';
import type { Metadata } from 'next';
import type { LocalParams } from 'next-intlayer';

export const generateMetadata = ({
  params: { locale },
}: LocalParams): Metadata => {
  const t = <T>(content: IConfigLocales<T>) =>
    getTranslationContent(content, locale);

  return {
    title: t<string>({
      en: 'My title',
      fr: 'Mon titre',
      es: 'Mi título',
    }),
    description: t({
      en: 'My description',
      fr: 'Ma description',
      es: 'Mi descripción',
    }),
};

// ... Rest of the code

(Optional) Step 9: Change the language of your content

To change the language of your content, you can use the setLocale function provided by the useLocale hook. This function allows you to set the locale of the application and update the content accordingly.

import { Locales } from "intlayer";
import { useLocale } from "next-intlayer";

const MyComponent = () => {
  const { setLocale } = useLocale();

  return (
    <button onClick={() => setLocale(Locales.English)}>Change Language</button>
  );
};

Configure TypeScript

Intlayer use module augmentation to get benefits of TypeScript and make your codebase stronger.

alt text

Ensure your TypeScript configuration includes the autogenerated types.

// tsconfig.json

{
  // your custom config
  include: [
    "src",
    "types", // <- Include the auto generated types
  ],
}

Git Configuration

It is recommended to ignore the files generated by Intlayer. This allows you to avoid committing them to your Git repository.

To do this, you can add the following instructions to your .gitignore file:

# Ignore the files generated by Intlayer
.intlayer