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Client Components

This guide explains how to use the internationalization package with React Client Components in your Next.js application.

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Overview

Client Components run in the browser and can include interactive features. To use translations in Client Components, you need to:
  1. Wrap your Client Components with the TranslationProvider in a Server Component
  2. Use the useTranslation hook in your Client Components to access translations

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Setting Up the Translation Provider

In a Server Component that renders your Client Component, wrap the Client Component with the TranslationProvider: 
// app/[locale]/contact/page.tsx (Server Component)
import { getDictionary } from '@repo/internationalization';
import { TranslationProvider } from '@repo/internationalization/TranslationProvider';
import ContactForm from '@/components/ContactForm'; // Client component

export default async function ContactPage({ params }: { params: { locale: string } }) {
  const dictionary = await getDictionary(params.locale);
  
  return (
    <div>
      <h1>{dictionary.web.contact.title}</h1>
      <p>{dictionary.web.contact.description}</p>
      
      <TranslationProvider locale={params.locale} messages={dictionary}>
        <ContactForm />
      </TranslationProvider>
    </div>
  );
}
The TranslationProvider component:
  • Takes the current locale and dictionary as props
  • Makes translations available to all Client Components within its subtree
  • Uses next-intl under the hood to provide translations

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Using the useTranslation Hook

In your Client Components, import and use the useTranslation hook to access translations: 
// components/ContactForm.tsx (Client Component)
'use client';

import { useState } from 'react';
import { useTranslation } from '@repo/internationalization/useTranslation';

export default function ContactForm() {
  const { t } = useTranslation('web.contact.form');
  const [formData, setFormData] = useState({
    name: '',
    email: '',
    message: ''
  });
  
  const handleChange = (e) => {
    const { name, value } = e.target;
    setFormData(prev => ({ ...prev, [name]: value }));
  };
  
  const handleSubmit = (e) => {
    e.preventDefault();
    // Form submission logic
  };
  
  return (
    <form onSubmit={handleSubmit}>
      <div className="form-group">
        <label htmlFor="name">{t('name')}</label>
        <input
          type="text"
          id="name"
          name="name"
          value={formData.name}
          onChange={handleChange}
          placeholder={t('namePlaceholder')}
          required
        />
      </div>
      
      <div className="form-group">
        <label htmlFor="email">{t('email')}</label>
        <input
          type="email"
          id="email"
          name="email"
          value={formData.email}
          onChange={handleChange}
          placeholder={t('emailPlaceholder')}
          required
        />
      </div>
      
      <div className="form-group">
        <label htmlFor="message">{t('message')}</label>
        <textarea
          id="message"
          name="message"
          value={formData.message}
          onChange={handleChange}
          placeholder={t('messagePlaceholder')}
          required
        ></textarea>
      </div>
      
      <button type="submit">{t('submit')}</button>
    </form>
  );
}
The useTranslation hook:
  • Takes a namespace parameter that specifies which part of the translation object to use
  • Returns a t function that you can use to access translations within that namespace
  • Automatically updates when the locale changes

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Namespace Parameter

The namespace parameter in the useTranslation hook helps you access a specific section of your translations: 
// Access translations under web.contact.form
const { t } = useTranslation('web.contact.form');

// Now you can use t('fieldName') instead of t('web.contact.form.fieldName')
t('name') // -> "Name"
t('email') // -> "Email"
You can use different namespaces in different components based on the section of translations they need: 
// In a navigation component
const { t } = useTranslation('web.header');

// In a footer component
const { t } = useTranslation('web.footer');

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Dynamic Values and Formatting

You can include dynamic values in your translations: 
// Translation: "Hello, {name}!"
const { t } = useTranslation('web.greeting');

// Pass values as an object
t('welcome', { name: user.name }) // -> "Hello, John!"
For date and number formatting: 
// Translation: "Last updated on {date}"
const { t } = useTranslation('web.common');

// Format date according to the current locale
const formattedDate = new Intl.DateTimeFormat(locale, {
  year: 'numeric',
  month: 'long',
  day: 'numeric'
}).format(new Date());

t('lastUpdated', { date: formattedDate })

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Pluralization

You can handle pluralization in your translations: 
// In your translation file:
// {
//   "items": {
//     "zero": "No items",
//     "one": "One item",
//     "other": "{count} items"
//   }
// }

const { t } = useTranslation('web.products');

// Pass the count as a parameter
t('items', { count: 0 }) // -> "No items"
t('items', { count: 1 }) // -> "One item"
t('items', { count: 5 }) // -> "5 items"

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Creating a Language Switcher

You can create a language switcher component to allow users to change the language: 
// components/LanguageSwitcher.tsx
'use client';

import Link from 'next/link';
import { usePathname } from 'next/navigation';
import { i18nConfig } from '@repo/internationalization/i18nConfig';
import { useTranslation } from '@repo/internationalization/useTranslation';

// Map of locale codes to their display names
const localeNames: Record<string, string> = {
  en: 'English',
  tr: 'Türkçe',
  es: 'Español',
  de: 'Deutsch'
};

export default function LanguageSwitcher() {
  const pathname = usePathname();
  const { t } = useTranslation('web.common');
  
  // Function to get the path for a different locale
  const getLocalePath = (locale: string) => {
    const segments = pathname.split('/');
    const currentLocale = segments[1];
    
    // Check if the current path already has a locale
    if (i18nConfig.locales.includes(currentLocale)) {
      segments[1] = locale;
      return segments.join('/');
    }
    
    // If no locale in the path, add it
    return `/${locale}${pathname}`;
  };
  
  return (
    <div className="language-switcher">
      <span className="language-label">{t('language')}:</span>
      <ul className="language-list">
        {i18nConfig.locales.map((locale) => (
          <li key={locale}>
            <Link 
              href={getLocalePath(locale)}
              className={pathname.startsWith(`/${locale}/`) ? 'active' : ''}
            >
              {localeNames[locale] || locale.toUpperCase()}
            </Link>
          </li>
        ))}
      </ul>
    </div>
  );
}

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Best Practices

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Examples

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Interactive Form with Validation

// components/SignupForm.tsx
'use client';

import { useState } from 'react';
import { useTranslation } from '@repo/internationalization/useTranslation';

type FormErrors = {
  name?: string;
  email?: string;
  password?: string;
};

export default function SignupForm() {
  const { t } = useTranslation('web.auth.signup');
  const [formData, setFormData] = useState({
    name: '',
    email: '',
    password: ''
  });
  const [errors, setErrors] = useState<FormErrors>({});
  
  const validate = () => {
    const newErrors: FormErrors = {};
    
    if (!formData.name) {
      newErrors.name = t('errors.nameRequired');
    }
    
    if (!formData.email) {
      newErrors.email = t('errors.emailRequired');
    } else if (!/\S+@\S+\.\S+/.test(formData.email)) {
      newErrors.email = t('errors.emailInvalid');
    }
    
    if (!formData.password) {
      newErrors.password = t('errors.passwordRequired');
    } else if (formData.password.length < 8) {
      newErrors.password = t('errors.passwordLength');
    }
    
    setErrors(newErrors);
    return Object.keys(newErrors).length === 0;
  };
  
  const handleChange = (e) => {
    const { name, value } = e.target;
    setFormData(prev => ({ ...prev, [name]: value }));
    
    // Clear error when user starts typing
    if (errors[name]) {
      setErrors(prev => ({ ...prev, [name]: undefined }));
    }
  };
  
  const handleSubmit = (e) => {
    e.preventDefault();
    
    if (validate()) {
      // Form submission logic
      console.log('Form submitted:', formData);
      alert(t('submitSuccess'));
    }
  };
  
  return (
    <form onSubmit={handleSubmit} className="signup-form">
      <h2>{t('title')}</h2>
      
      <div className="form-group">
        <label htmlFor="name">{t('name')}</label>
        <input
          type="text"
          id="name"
          name="name"
          value={formData.name}
          onChange={handleChange}
          className={errors.name ? 'error' : ''}
        />
        {errors.name && <span className="error-message">{errors.name}</span>}
      </div>
      
      <div className="form-group">
        <label htmlFor="email">{t('email')}</label>
        <input
          type="email"
          id="email"
          name="email"
          value={formData.email}
          onChange={handleChange}
          className={errors.email ? 'error' : ''}
        />
        {errors.email && <span className="error-message">{errors.email}</span>}
      </div>
      
      <div className="form-group">
        <label htmlFor="password">{t('password')}</label>
        <input
          type="password"
          id="password"
          name="password"
          value={formData.password}
          onChange={handleChange}
          className={errors.password ? 'error' : ''}
        />
        {errors.password && <span className="error-message">{errors.password}</span>}
      </div>
      
      <div className="form-actions">
        <button type="submit">{t('submit')}</button>
      </div>
      
      <p className="terms">{t('termsNotice')}</p>
    </form>
  );
}

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Dynamic Content Loading

// components/DynamicContent.tsx
'use client';

import { useState, useEffect } from 'react';
import { useTranslation } from '@repo/internationalization/useTranslation';

export default function DynamicContent() {
  const { t } = useTranslation('web.dashboard');
  const [data, setData] = useState(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState(null);
  
  useEffect(() => {
    async function fetchData() {
      try {
        setLoading(true);
        const response = await fetch('/api/data');
        const result = await response.json();
        setData(result);
        setError(null);
      } catch (err) {
        setError(t('errors.fetchFailed'));
      } finally {
        setLoading(false);
      }
    }
    
    fetchData();
  }, [t]);
  
  if (loading) {
    return <div className="loading">{t('loading')}</div>;
  }
  
  if (error) {
    return <div className="error">{error}</div>;
  }
  
  return (
    <div className="dynamic-content">
      <h2>{t('dataTitle')}</h2>
      
      {data && data.items && data.items.length > 0 ? (
        <ul className="data-list">
          {data.items.map((item, index) => (
            <li key={index} className="data-item">
              <h3>{item.title}</h3>
              <p>{item.description}</p>
              <span className="date">
                {t('lastUpdated', { 
                  date: new Date(item.updatedAt).toLocaleDateString() 
                })}
              </span>
            </li>
          ))}
        </ul>
      ) : (
        <p className="no-data">{t('noData')}</p>
      )}
    </div>
  );
}

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Next Steps

Adding Languages

Learn how to add support for new languages

Advanced Usage

Advanced internationalization techniques