In fact, NG-ALAIN did initially rely on ngx-translate as part of its internationalization.

However, over time, it was discovered that if internationalization data can be confirmed at the Angular startup, the implementation method of ngx-translate is not as developer-friendly.

Therefore, NG-ALAIN provides a simplified approach, which assumes that internationalization data is always ready to be used. Of course, aside from relying on APP_INITIALIZER, current route guards can also address the issue of establishing internationalization data with delayed routes.

For refreshing internationalization, I believe using location.reload() might slightly affect the experience, but from a development perspective, it is more worthwhile.

NG-ALAIN does not strictly enforce using the default implementation and can fully utilize DI rules to override this default behavior.

Do you mean override the Pipe itself?

The contract seems to be that AlainI18NService.change is an event fired when the AlainI18NService state changes (selected language or current set of translations), yet this is not being honored by the current I18nPipe. The simple fact is that I18nPipe is not a pure since it depends on AlainI18NService state. This is a bug that should be fixed. The UX of reloading is ugly and unnecessary.

A very simple caching strategy (like the one linked to above in ngx-translate) is cheap to evaluate and would have negligible impact on runtime performance. The ngx-translate license is very permissive. You could event borrow their implementation as long as you attribute it properly.

Angular's dependency injection can help you override NG-ALAIN's default behavior, including I18nPipe. In fact, you only need to ensure the implementation of ALAIN_I18N_TOKEN (which internally provides a default behavior via AlainI18nBaseService). Since the entire @delon/* library involves a lot of internationalization, everything depends on ALAIN_I18N_TOKEN. How you implement internationalization is entirely up to you. Otherwise, NG-ALAIN’s default implementation will be used.