fix:#5 readded missing locale function for dom

frontend/src/i18n/index.ts

@@ -20,6 +20,18 @@ function setup() {
   return _i18n;
 }
 
+// Sets the active locale.
+function setLocale(newLocale: any) {
+  _i18n.global.locale = newLocale;
+  setDocumentAttributesFor(newLocale);
+}
+
+function setDocumentAttributesFor(locale: any) {
+  const htmlElement = document.querySelector("html");
+
+  htmlElement?.setAttribute("lang", locale);
+}
+
 // Public interface
 export default {
   // Expose the VueI18n instance via a getter
@@ -27,4 +39,5 @@ export default {
     return _i18n;
   },
   setup,
+  setLocale,
 };