diff --git a/src/middleware.ts b/src/middleware.ts
index 64400dc..84600ad 100644
--- a/src/middleware.ts
+++ b/src/middleware.ts
@@ -15,8 +15,10 @@ export const hashSecret = async (secret: string) => {
 };
 
 export const datocms = defineMiddleware(async ({ locals }, next) => {
-  locals.datocmsEnvironment = datocmsEnvironment;
-  locals.datocmsToken = getSecret('DATOCMS_READONLY_API_TOKEN');
+  Object.assign(locals, {
+    datocmsEnvironment: datocmsEnvironment,
+    datocmsToken: getSecret('DATOCMS_READONLY_API_TOKEN')
+  });
   const response = await next();
   return response;
 });
@@ -32,16 +34,18 @@ const i18n = defineMiddleware(async ({ params, request }, next) => {
     Object.assign(params, { locale });
   }
   setLocale(params.locale as SiteLocale);
-  
+
   const response = await next();
   return response;
 });
 
 const preview = defineMiddleware(async ({ cookies, locals }, next) => {
-  const previewSecret = getSecret('HEAD_START_PREVIEW_SECRET');
-  locals.isPreview = getSecret('HEAD_START_PREVIEW');
-  locals.isPreviewAuthOk = Boolean(previewSecret) && cookies.get(previewCookieName)?.value === await hashSecret(previewSecret);
-  locals.previewSecret = previewSecret;
+  const previewSecret = getSecret('HEAD_START_PREVIEW_SECRET') || '';
+  Object.assign(locals, {
+    isPreview: getSecret('HEAD_START_PREVIEW'),
+    isPreviewAuthOk: Boolean(previewSecret) && cookies.get(previewCookieName)?.value === await hashSecret(previewSecret),
+    previewSecret: previewSecret
+  });
   const response = await next();
 
   if (locals.isPreview) {