up: collection add new method: getSub

Author: inhere

src/Std/Collection.php

@@ -201,10 +201,21 @@ public function mapObject(string $key, string|object $obj): object
         if ($data = $this->getArray($key)) {
             Php::initObject($obj, $data);
         }
-
         return $obj;
     }
 
+    /**
+     * Get data as sub collection
+     *
+     * @param string $key
+     *
+     * @return static
+     */
+    public function getSub(string $key): static
+    {
+        return static::new($this->getArray($key));
+    }
+
     /**
      * Add item to collection
      *