Intlayer: Next-Level Content Management in JavaScript

Intlayer is an internationalization library designed specifically for JavaScript developers. It allow the declaration of your content everywhere in your code. It converts declaration of multilingual content into structured dictionaries to integrate easily in your code. Using TypeScript, Intlayer make your development stronger and more efficient.

Example of usage

.
├── ClientComponent
│   ├── index.content.ts
│   └── index.tsx
└── ServerComponent
    ├── index.content.ts
    └── index.tsx

// ./ClientComponent/index.content.ts

import { DeclarationContent, t } from "intlayer";

const clientComponentContent = {
  key: "client-component",
  content: {
    myTranslatedContent: t({
      en: "Hello World",
      fr: "Bonjour le monde",
      es: "Hola Mundo",
    }),
  },
} satisfies DeclarationContent;

export default clientComponentContent;

// ./ClientComponent/index.tsx
"use client";

import { useIntlayer } from "next-intlayer";

export const ClientComponent = () => {
  const { myTranslatedContent } = useIntlayer("client-component");

  return <span>{myTranslatedContent}</span>;
};

Why Choose Intlayer?

• JavaScript-Powered Content Management: Harness the flexibility of JavaScript to define and manage your content efficiently.
• Type-Safe Environment: Leverage TypeScript to ensure all your content definitions are precise and error-free.
• Integrated Content Files: Keep your translations close to their respective components, enhancing maintainability and clarity.
• Simplified Setup: Get up and running quickly with minimal configuration, especially optimized for Next.js projects.
• Server Component Support: Perfectly suited for Next.js server components, ensuring smooth server-side rendering.
• Enhanced Routing: Full support for Next.js app routing, adapting seamlessly to complex application structures.

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]/metadata.ts

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',
    }),

};

(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.

Ensure your TypeScript configuration includes the autogenerated types.

// tsconfig.json

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