Localization

Translations work as Laravel's: keyed lines with a fallback locale, JSON lines keyed by the text itself, :name placeholders and plural lines, with the active locale held per request, so concurrent requests in different languages never see each other's.

Lines#

Keyed lines (Laravel's lang/<locale>/*.php) are registered in bootstrap/app.dart; nested maps become dotted keys:

Application.configure(basePath: '.')
    .withTranslations({
      'en': {
        'auth': {'failed': 'These credentials do not match our records.'},
        'exam.welcome': 'Welcome, :name!',
        'exam.minutes': '{1} :count minute left|[2,*] :count minutes left',
      },
      'id': {
        'auth.failed': 'Kredensial ini tidak cocok dengan data kami.',
        'exam.welcome': 'Selamat datang, :name!',
        'exam.minutes': ':count menit tersisa',
      },
    })

JSON lines are read from lang/<locale>.json at boot, the same files a Laravel application uses, so the two can share them:

{"Log in": "Masuk", "Forgot your password?": "Lupa kata sandi?"}

Ship the lang/ directory next to the binary, as .env.

Translating#

trans('exam.welcome', {'name': 'teo'});        // Welcome, teo!
trans('Log in');                               // Masuk (locale id)
transChoice('exam.minutes', 5);                // 5 minutes left
Lang.get('auth.failed', const {}, 'id');       // a given locale
Lang.has('exam.welcome');

trans is Laravel's __() and trans(): Dart keeps a leading underscore for private names, so there is no __. A missing key returns the key. :name takes the value as given, :Name capitalises it and :NAME upper-cases it; the longest placeholder wins and replaced text is not scanned again, as PHP's strtr.

transChoice (Laravel's trans_choice) fills :count and picks the form: an explicit {n} or [from,to] segment (* for an open end) that matches, otherwise the locale's plural form. The plural rules are Laravel's, for 280 locales, so apple|apples is apples for 0 in English, and Indonesian, which has one form, always uses the first.

Keyed lines fall back to APP_FALLBACK_LOCALE (default en); JSON lines do not, as in Laravel.

The current locale#

APP_LOCALE is the application locale. App.setLocale('id') changes it for the rest of the current request, job or command, and App.locale reads it. SetLocaleMiddleware picks it from ?lang= or the Accept-Language header among the locales you support:

.withMiddleware((middleware) {
  middleware.use(const [SetLocaleMiddleware(supported: ['en', 'id'])]);
})

Validation messages follow the current locale (English and Indonesian are bundled).