Import Excel using Codeigniter 4 and Ajax

public function fileUpload()
    {
        if($this->request->isAJAX())
        {
            $data = array();

            // Read new token and assign to $data['token']
            $data['token'] = csrf_hash();

            $validation = \Config\Services::validation();

            $valid = $this->validate([
                'fileimport' => [
                    'label' => 'File',
                    'rules' => 'uploaded[partexcel]|ext_in[partexcel,xls,xlsx]',
                    'errors' => [
                        'uploaded' => 'tidak boleh kosong',
                        'ext_in'    => 'harus extensi xls / xlsx'
                    ]
                ]
            ]);

            if($valid)
            {
                $msg = [
                    'error' => [
                        'fileimport'  => $validation->getError('fileimport')
                    ]
                ];
            }else{
                $file_excel = $this->request->getFile('file');
                //function cek nama file -----------------
                // $nama_file = $file_excel->getName();

                $ext = $file_excel->getClientExtension();
                if($ext == 'xls')
                {
                    $render = new \PhpOffice\PhpSpreadsheet\Reader\Xls();
                }else{
                    $render = new \PhpOffice\PhpSpreadsheet\Reader\Xlsx();
                }
                $spreadsheet = $render->load($file_excel);

                $data = $spreadsheet->getActiveSheet()->toArray();

                // Kita kumpulkan dulu data dari excel ke $data_excel biar mudah dibaca
                $data_excel = [];

                $flag = TRUE;
                $flag_input = TRUE;

                foreach($data as $x => $row)
                {
                    if($x == 0)
                    {
                        continue;
                    }

                    $part_code = $row[0];
                    $part_name = $row[1];
                    $kode_gudang = $row[2];
                    $part_location = $row[3];
                    $part_qty_reel = $row[4];

                    $db = \Config\Database::connect();

                    $sql_cek = $db->table('m_part')->getWhere(['part_code'=>$part_code])->getResult();

                    if($sql_cek) {
                        $flag = FALSE;
                    } else {
                        $flag = TRUE;
                    }
                }

                if($flag === FALSE) {
                    $respon = 2;
                    $pesan = "Part ada yang sudah terdaftar";
                } else {
                    foreach($data as $x => $row)
                    {
                        if($x == 0)
                        {
                            continue;
                        }

                        $part_code = $row[0];
                        $part_name = $row[1];
                        $kode_gudang = $row[2];
                        $part_location = $row[3];
                        $part_qty_reel = $row[4];

                        $simpandata = [
                            'part_code' => $part_code,
                            'part_name' => $part_name,
                            'part_wh_code' => $kode_gudang,
                            'part_location' => $part_location,
                            'part_qty_reel' => $part_qty_reel,
                            'created_by'    => $this->session->get('user_name'),
                            'created_date'  => date('Y-m-d H:i:s')
                        ];

                        $sql = $this->m_part->insert($simpandata);
                        $respon = 1;
                        $pesan = "Part berhasil ditambahkan";
                        /*if($sql) {
                            $flag_input = FALSE;
                        } else {
                            $flag_input = TRUE;
                        }*/
                    }

                    /*if($flag_input === FALSE)
                    {
                        $respon = 1;
                        $pesan = "Part berhasil ditambahkan";
                    }else{
                        $respon = 0;
                        $pesan = "Part gagal ditambahkan!";
                    }*/
                }

                $msg = [
                    'res' => $respon,
                    'pesan' => $pesan
                ];
            }

            echo json_encode($msg);
        }else{
            exit('Maaf request tidak dapat diproses!');
        }

    }