#428

frontend/src/lib/i18n.ts

@@ -0,0 +1,56 @@
+import { createInstance } from 'i18next'
+import { initReactI18next } from 'react-i18next'
+
+import ainuNavigation from '@/locales/ain-Kana/navigation.json'
+import nipponeseNavigation from '@/locales/ja/navigation.json'
+
+import type { LocaleCode } from '@/lib/locales'
+
+export const i18n = createInstance ()
+
+void i18n.use (initReactI18next).init ({
+    lng: 'ja',
+    fallbackLng: 'ja',
+    supportedLngs: ['ja', 'ain-Kana'],
+    load: 'currentOnly',
+    initAsync: false,
+    defaultNS: 'navigation',
+    ns: ['navigation'],
+    resources: {
+	ja: { navigation: nipponeseNavigation },
+	'ain-Kana': { navigation: ainuNavigation } },
+    interpolation: { escapeValue: false },
+    returnNull: false,
+    returnEmptyString: false,
+    saveMissing: import.meta.env.DEV,
+    missingKeyHandler: (languages, namespace, key) => {
+      console.warn ('[i18n] missing key', { languages, namespace, key })
+    },
+    react: { useSuspense: false } })
+
+
+export const untranslatedKeys = (
+    locale: LocaleCode,
+    namespace = 'navigation',
+): string[] => {
+  const collect = (resource: Record<string, unknown>, prefix = ''): string[] =>
+      Object.entries (resource).flatMap (([key, value]) => {
+	const path = prefix ? `${ prefix }.${ key }` : key
+	return (value != null && typeof value === 'object')
+	    ? collect (value as Record<string, unknown>, path)
+	    : [path]
+      })
+  const baseline = i18n.getResourceBundle ('ja', namespace) ?? { }
+  return collect (baseline).filter (key => {
+    const value = i18n.getResource (locale, namespace, key)
+    return typeof value !== 'string' || value.length === 0
+  })
+}
+
+
+if (import.meta.env.DEV)
+{
+  const missing = untranslatedKeys ('ain-Kana')
+  if (missing.length > 0)
+    console.warn ('[i18n] ain-Kana: untranslated navigation keys', missing)
+}