Before running parse operation on search results page it checks now if there are any books to parse.

src/DataParser.php

@@ -49,6 +49,7 @@ class DataParser
         $books = $document->find('#search .authorAllBooks__single');
 
         $booksInfo = [];
+        if ($document->has('#searchksiazki')) {
             foreach ($books as $book) {
                 $bookInfo = new Info();
                 $bookInfo->title = trim($book->first('.authorAllBooks__singleTextTitle')->text());
@@ -57,6 +58,7 @@ class DataParser
                 $bookInfo->cover_url = $this->generateCoverUrls($book->first('.img-fluid')->getAttribute('data-src'));
                 $booksInfo[] = $bookInfo;
             }
+        }
         return $booksInfo;
     }