Next.jsアプリに多言語対応を追加。

// This repository: frontend/scripts/translate-messages.mjs
// Chunks large namespaces (e.g. home) so the model stays within output limits.
//
//   export POLYLINGO_API_KEY=pl_xxx
//   npm run i18n:polylingo
//
// Writes messages/es.json, fr.json, … from messages/en.json via POST /v1/translate
// with format: "json". See MARKETING_I18N.md for options and CI notes.
//
// Minimal one-shot pattern (fine for small message files):
//
// const source = readFileSync('./messages/en.json', 'utf8')
// const { translations } = await fetch(apiUrl + '/translate', {
//   method: 'POST',
//   headers: { Authorization: `Bearer ${apiKey}`, 'Content-Type': 'application/json' },
//   body: JSON.stringify({
//     content: source, format: 'json', source: 'en',
//     targets: ['es', 'fr', 'de'], model: 'standard',
//   }),
// }).then((r) => r.json())
//
// for (const [lang, raw] of Object.entries(translations)) {
//   const obj = typeof raw === 'string' ? JSON.parse(raw) : raw
//   writeFileSync(`./messages/${lang}.json`, JSON.stringify(obj, null, 2))
// }

// i18n.ts (next-intl v4)
import { getRequestConfig } from 'next-intl/server'

export const locales = [
  'en', 'ar', 'bn', 'cs', 'da', 'de', 'el', 'es', 'fa', 'fi',
  'fr', 'he', 'hi', 'id', 'it', 'ja', 'ko', 'ms', 'nl', 'no',
  'pl', 'pt', 'ru', 'sv', 'sw', 'th', 'tr', 'uk', 'vi', 'zh',
] as const
export type Locale = (typeof locales)[number]

export default getRequestConfig(async ({ requestLocale }) => {
  const locale = await requestLocale
  return {
    locale,
    messages: (await import(`./messages/${locale}.json`)).default,
  }
})

// package.json
{
  "scripts": {
    "dev": "next dev",
    "build": "next build",
    "i18n:polylingo": "node scripts/translate-messages.mjs",
    "translate:build": "npm run i18n:polylingo && next build"
  }
}