Internationalization

Use stable message identifiers and named placeholders. Do not concatenate translated fragments or use English text as an identifier. Choose plural forms from locale rules rather than count === 1.

AngularTS formatting filters delegate to Intl. Pass the application locale and explicit currency or time-zone policy; browser defaults may differ from user settings.

<span>{{ total | currency:user.locale }}</span>
<time>{{ dueAt | date:user.locale }}</time>

A locale service should deduplicate catalog requests, cache by locale and catalog version, and expose loading and fallback state. Do not render raw message identifiers while loading.

Set document or feature lang and dir. Prefer logical CSS properties. Test long labels, narrow screens, mixed-direction names, non-Latin input, plural edge cases, currency minor units, and dates around daylight-saving transitions.

Locale switching should invalidate message and formatter readers without rebuilding unrelated domain state.