Error cannot read property 'replace' of undefined rowGroup

I try code like on this page how to start and end grouping with counting salary. But I have Uncaught TypeError: Cannot read property 'replace' of undefined on line return a + b.replace(/[^\d]/g, '')*1;
My Controller like this

function viewAnggaran(){
        $data = $this->m_anggaran->anggaran();
        foreach($data as $p) {
            $query[] = array(
                'kd_anggaran'   => '<a href="javascript:void(0)" id="btn-detail" data-toggle="modal" title="Detail" data-kode='.$p->kode_anggaran.' data-tahun='.$p->thn_anggaran.' data-nama_unit='.$p->nama_unit.' data-ruangan='.$p->nama_ruangan.'>'.$p->kode_anggaran.'</a>',
                'unit'          => $p->nama_unit,
                'ruangan'       => $p->nama_ruangan,
                'tahun'         => $p->thn_anggaran,
                'barang'        => $p->nama_barang,
                'jumlah'        => $p->jml_barang,
                'satuan'        => rupiah($p->nilai),
                'harga'         => rupiah($p->Anggaran),
                'edit'          => anchor('anggaran/edit/'.$p->kode_anggaran,'<i class="btn btn-info btn-sm glyphicon glyphicon-edit" data-toggle="tooltip" title="Edit"></i>'),
                'hapus'         => anchor('anggaran/delete/' . $p->kode_anggaran, '<i class="btn-sm btn-danger glyphicon glyphicon-trash" data-toggle="tooltip" title="Delete"></i>', array('onclick' => "return confirm('Data Akan di Hapus?')"))
            );
        }
        $result=array('data'=>$query);
        echo  json_encode($result);
    }

My view:

$.fn.dataTable.ext.errMode = 'throw'; 
        $('#tb-anggaran').dataTable( {
            Processing: true, 
            ServerSide: true,
            iDisplayLength: 25,
            oLanguage: {
                sSearch: "Pencarian Data :  ",
                sZeroRecords: "Tidak Ada Data yg ditampilkan",
                sEmptyTable: "Tidak ada data yang tersedia di tabel"
            },
            dom: 'Bfrtip',
            select: true,
            responsive: true,
            orderFixed: [[1, 'asc'], [0, 'asc']],
            buttons: [
                {
                    extend: 'print',
                    exportOptions: {
                    columns: ':visible',
                    stripHtml: false,
                    }
                },
                {
                    extend: 'excelHtml5',
                    title: 'Laporan Anggaran Per Ruang',
                    exportOptions: {
                    columns: ':visible',
                    stripHtml: false,
                    }
                },
                'colvis'
            ],
            columnDefs: [{
                targets: [ 0, 1, -1 ],
                visible: false
            }],
            ajax: "<?php echo base_url('anggaran/viewAnggaran');?>",
            columns: [
                    { "mData": "kd_anggaran" },
                    { "mData": "unit"},
                    { "mData": "ruangan" },
                    { "mData": "tahun" },
                    { "mData": "barang" },
                    { "mData": "jumlah" },
                    { "mData": "satuan" },
                    { "mData": "harga" },
                    { "mData": "edit" }, 
                    { "mData": "hapus" }, 
                    ],
            rowGroup: {
                endRender: function ( rows, group ) {
                var salaryAvg = rows
                    .data()
                    .pluck(7)
                    .reduce( function (a, b) {
                        return a + b.replace(/[^\d]/g, '')*1;
                    }, 0);
                salaryAvg = $.fn.dataTable.render.number('.', '.', 0, 'Rp ').display( salaryAvg );
                return $('<tr/>')
                    .append( '<td colspan="5">Total Anggaran '+group+'</td>' )
                    .append( '<td>'+salaryAvg+'</td>' )
                    .append( '<td/>' );
                },
                dataSrc: [ 1, 0 ]
            }
        });

Please, help me

Edited by Colin - Syntax highlighting. Details on how to highlight code using markdown can be found in this guide.