Internationalization (i18n) in Next.js

What You’ll Learn 📚

In this tutorial, you’ll learn:

• What internationalization (i18n) is and why it’s important
• Key terminology and concepts in i18n
• How to implement i18n in a Next.js application
• Common challenges and how to troubleshoot them
• Hands-on examples to solidify your understanding

Introduction to Internationalization (i18n)

Internationalization, often abbreviated as i18n (because there are 18 letters between the ‘i’ and ‘n’), is the process of designing your application so it can be adapted to various languages and regions without engineering changes. This is crucial if you want your app to reach a global audience. 🌐

Key Terminology

• Localization (l10n): Adapting your app for a specific locale or market, including language, currency, and cultural nuances.
• Locale: A set of parameters that defines the user’s language, region, and any special variant preferences.
• Translation: The process of converting text from one language to another.

Getting Started with i18n in Next.js

The Simplest Example

Let’s start with a basic example to get the ball rolling. 🎳

# Step 1: Create a new Next.js app
npx create-next-app@latest my-i18n-app

# Step 2: Navigate into your project directory
cd my-i18n-app

// next.config.js
module.exports = {
  i18n: {
    locales: ['en', 'fr'], // English and French
    defaultLocale: 'en',
  },
};

Progressively Complex Examples

Example 1: Basic Page Translation

Let’s create a simple page with translations.

// pages/index.js
import { useRouter } from 'next/router';

const Home = () => {
  const { locale } = useRouter();
  const t = {
    en: { welcome: 'Welcome to our site!' },
    fr: { welcome: 'Bienvenue sur notre site!' },
  };

  return 
{t[locale].welcome}
;
};

export default Home;

Example 2: Dynamic Routing with i18n

Now, let’s see how dynamic routing works with i18n.

// pages/[lang]/about.js
import { useRouter } from 'next/router';

const About = () => {
  const { query } = useRouter();
  const t = {
    en: { about: 'About Us' },
    fr: { about: 'À propos de nous' },
  };

  return 
{t[query.lang].about}
;
};

export default About;

Example 3: Using a Translation Library

For more complex applications, you might want to use a translation library like next-i18next.

# Install next-i18next
npm install next-i18next react-i18next i18next

// i18n.js
const NextI18Next = require('next-i18next').default;

module.exports = new NextI18Next({
  defaultLanguage: 'en',
  otherLanguages: ['fr'],
});

// pages/_app.js
import App from 'next/app';
import { appWithTranslation } from '../i18n';

class MyApp extends App {
  render() {
    const { Component, pageProps } = this.props;
    return ;
  }
}

export default appWithTranslation(MyApp);

Common Questions and Answers

1. What is the difference between i18n and l10n?

   i18n is about preparing your app for localization, while l10n is the actual adaptation to a specific locale.

2. Why is i18n important?

   It allows your app to reach a wider audience by supporting multiple languages and regional settings.

3. How do I switch languages in a Next.js app?

   You can use the useRouter hook to access the current locale and change it based on user interaction.

4. Can I use i18n with dynamic content?

   Yes, you can translate dynamic content by using translation functions or libraries like next-i18next.

5. What are common pitfalls in i18n?

   Forgetting to update translations, hardcoding strings, and not considering right-to-left languages.

Troubleshooting Common Issues

If your translations aren’t showing up, make sure your locale files are correctly set up and that you’re accessing the right keys.

Remember to test your app in all supported languages to catch any issues early!

Practice Exercises

• Create a new page and add translations for at least two languages.
• Try adding a third language to your app and update the translations accordingly.
• Experiment with a translation library and compare it with your manual implementation.

Don’t worry if this seems complex at first. With practice, you’ll become more comfortable with internationalization in Next.js. Keep experimenting and learning! 🚀

Further Resources

• Next.js i18n Documentation
• React i18next Documentation