update code

app/Exports/PrivateDocumentsExport.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace App\Exports;
+
+use PhpOffice\PhpSpreadsheet\Shared\Date;
+
+class PrivateDocumentsExport extends BaseDocumentsExport
+{
+    public function headings(): array
+    {
+        return [
+            'Ngày ban hành',
+            'Ký hiệu',
+            'Loại',
+            'Trích yếu',
+            'Người nhận',
+        ];
+    }
+
+    /**
+     * @param mixed $document
+     *
+     * @return array
+     */
+    public function map($document): array
+    {
+        return [
+            Date::dateTimeToExcel($document->effective_at),
+            $document->symbol,
+            $document->type->name,
+            $document->abstract,
+            implode(', ', ($document->organizes->map(function($organize){
+                return $organize->name;
+            }))->toArray()),
+        ];
+    }
+
+}