diff --git a/src/services/Indexes.php b/src/services/Indexes.php
index a5ab49e..4107f05 100644
--- a/src/services/Indexes.php
+++ b/src/services/Indexes.php
@@ -461,13 +461,14 @@ public function buildMapping(): array
         $mapping = [];
 
         $predefinedAttributes = [
-            'title',
-            'slug',
+            'title' => 'text',
+            'slug' => 'text',
+            'postDate' => 'date'
         ];
 
-        foreach ($predefinedAttributes as $attribute) {
+        foreach ($predefinedAttributes as $attribute => $type) {
             $mapping[$fieldPrefix . 'attribute_' . $attribute] = [
-                'type' => 'text',
+                'type' => $type,
                 'analyzer' => 'standard',
             ];
         }