I am trying to set app locale in Laravel 11 with Inertia.js.
Here is the links to set locale:

<DropdownLink :href="route('set-language', { lang: 'lv' })">
    <div class="flex items-center">
         <img src="../../images/icons/latvian.png" :alt="$t('locales.lv')" height="25px" width="25px">
         <span class="ml-2">{{ $t('locales.lv') }}</span>
   </div>
</DropdownLink>

<DropdownLink :href="route('set-language', { lang: 'en' })">
    <div class="flex items-center">
          <img src="../../images/icons/english.png" :alt="$t('locales.en')" height="25px" width="25px">
           <span class="ml-2">{{ $t('locales.en') }}</span>
    </div>
</DropdownLink>

Controller action:

public function setLanguage(string $lang)
{
   Session::put('language', $lang);

   return Inertia::location(url()->previous());
}

Middleware (added to controller’s action route):

public function handle(Request $request, Closure $next)
{
   if (Session::has('language')){
       App::setLocale(Session::get('language'));
   }

   return $next($request)
       ->withCookie(
            cookie()->forever(
                'language',
                 Session::has('language') ? Session::get('language') : 'lv',
                 null,
                 null,
                 null,
                 false
              )
         );
}

App starting point:

const getLocale = (localeCookie) => {
    const localeName = document.cookie.match(new RegExp('(^| )' + localeCookie + '=([^;]+)'));

    return localeName
        ? localeName[2]
        : 'lv';
};

const locale = getLocale('language');

const i18n = setupI18n({locale});
loadLocaleMessages(i18n, locale);
const { t } = i18n.global;

The problem is that locale in laravel is not setting. I have dd() app locale and it’s correct but in application it still remains ‘en’.

So in my language selector where I conditionally show language flag, it’s always showing english flag.

<div class="flex items-center"> 
   <img v-if="$page.props.locale === 'en'" src="../../images/icons/english.png" :alt="$t('locales.en')" height="25px" width="25px">
   <img v-if="$page.props.locale === 'lv'" src="../../images/icons/latvian.png" :alt="$t('locales.lv')" height="25px" width="25px">
</div>