fix: use language facetfilter with locales only

src/client/theme-default/Layout.vue

@@ -3,7 +3,12 @@
     <NavBar v-if="showNavbar" @toggle="toggleSidebar">
       <template #search>
         <slot name="navbar-search">
-          <AlgoliaSearchBox v-if="theme.algolia" :options="theme.algolia" :key="siteRouteData.lang" />
+          <AlgoliaSearchBox
+            v-if="theme.algolia"
+            :options="theme.algolia"
+            :multilang="theme.locales"
+            :key="siteRouteData.lang"
+          />
         </slot>
       </template>
     </NavBar>

src/client/theme-default/components/AlgoliaSearchBox.vue

@@ -14,7 +14,8 @@ import { useSiteDataByRoute } from 'vitepress'
 const siteData = useSiteDataByRoute()
 
 const props = defineProps<{
-  options: DefaultTheme.AlgoliaSearchOptions
+  options: DefaultTheme.AlgoliaSearchOptions,
+  multilang?: boolean
 }>()
 
 const vm = getCurrentInstance()
@@ -57,6 +58,10 @@ function update(options: any) {
 }
 
 function initialize(userOptions: any) {
+  // if the user has multiple locales, the search results should be filtered
+  // based on the language
+  const facetFilters = props.multilang ? ['language:' + siteData.value.lang] : []
+
   docsearch(
     Object.assign({}, userOptions, {
       container: '#docsearch',
@@ -64,7 +69,7 @@ function initialize(userOptions: any) {
       searchParameters: Object.assign({}, userOptions.searchParameters, {
         // pass a custom lang facetFilter to allow multiple language search
         // https://github.com/algolia/docsearch-configs/pull/3942
-        facetFilters: ['language:' + siteData.value.lang].concat(
+        facetFilters: facetFilters.concat(
           userOptions.facetFilters || []
         )
       }),