Custom filter datatables serverside not working in codeigniter 3 - codeigniter

Question

Custom filter datatables serverside not working in codeigniter 3 but no error, with join table database ... anyone can help me ? thx
MODEL
Rekap_m.php
var $column_order = array(null, 'bidang', 'skpd', 'kode', 'masalah', 'nomor', 'rincian_masalah', 'tahun_cipta', 'rak', 'dos', 'retensi', 'ket');
var $column_search = array('bidang', 'kode', 'nomor', 'skpd');
var $order = array('id_arsip' => 'asc');
private function _get_datatables_query()
{
if ($this->input->post('bidang')) {
$this->db->where('id_bidang', $this->input->post('bidang'));
}
if ($this->input->post('skpd')) {
$this->db->like('skpd', $this->input->post('skpd'));
}
if ($this->input->post('kode')) {
$this->db->like('kode', $this->input->post('kode'));
}
if ($this->input->post('masalah')) {
$this->db->like('masalah', $this->input->post('masalah'));
}
$this->db->select('*');
$this->db->from('arsip');
$this->db->join('bidang', 'bidang.id_bidang = arsip.id_bidang');
$i = 0;
foreach ($this->column_search as $item) {
if (#$_POST['search']['value']) {
if ($i === 0) {
$this->db->group_start();
$this->db->like($item, $_POST['search']['value']);
} else {
$this->db->or_like($item, $_POST['search']['value']);
}
if (count($this->column_search) - 1 == $i)
$this->db->group_end();
}
$i++;
}
if (isset($_POST['order'])) {
$this->db->order_by($this->column_order[$_POST['order']['0']['column']], $_POST['order']['0']['dir']);
} else if (isset($this->order)) {
$order = $this->order;
$this->db->order_by(key($order), $order[key($order)]);
}
}
function get_datatables()
{
$this->_get_datatables_query();
if (#$_POST['length'] != -1)
$this->db->limit(#$_POST['length'], #$_POST['start']);
$query = $this->db->get();
return $query->result();
}
function count_filtered()
{
$this->_get_datatables_query();
$query = $this->db->get();
return $query->num_rows();
}
function count_all()
{
$this->db->from('arsip');
return $this->db->count_all_results();
}
public function get_list_bidangs()
{
$this->db->select('*');
$this->db->from('arsip');
$this->db->join('bidang', 'bidang.id_bidang = arsip.id_bidang');
$this->db->order_by('id_arsip', 'asc');
$query = $this->db->get();
$result = $query->result();
$bidangs = array();
foreach ($result as $row) {
$bidangs[] = $row->bidang;
}
return $bidangs;
}
CONTROLLER
Rekap.php
function __construct()
{
parent::__construct();
check_not_login();
$this->load->model('rekap_m');
}
public function index()
{
$bidangs = $this->rekap_m->get_list_bidangs();
$opt = array('' => 'Semua Bidang');
foreach ($bidangs as $id_bidang) {
$opt[$id_bidang] = $id_bidang;
}
$data['form_bidang'] = form_dropdown('', $opt, '', 'id="bidang" class="form-control"');
$this->template->load('template', 'rekap/rekap_data', $data);
}
function ajax_list()
{
$list = $this->rekap_m->get_datatables();
$data = array();
$no = #$_POST['start'];
foreach ($list as $arsip) {
$no++;
$row = array();
$row[] = $no . ".";
$row[] = $arsip->bidang;
$row[] = $arsip->skpd;
$row[] = $arsip->kode;
$row[] = $arsip->masalah;
$row[] = $arsip->nomor;
$row[] = $arsip->rincian_masalah;
$row[] = $arsip->tahun_cipta;
$row[] = $arsip->rak;
$row[] = $arsip->dos;
$row[] = $arsip->retensi;
$row[] = $arsip->ket;
// add html for action
$data[] = $row;
}
$output = array(
"draw" => #$_POST['draw'],
"recordsTotal" => $this->rekap_m->count_all(),
"recordsFiltered" => $this->rekap_m->count_filtered(),
"data" => $data,
);
// output to json format
echo json_encode($output);
}
public function rekap()
{
$this->load->model('bidang_m');
$data['bidang'] = $this->bidang_m->get()->result();
$this->template->load('template', 'rekap/rekap_data', $data);
}
public function del($id)
{
$this->arsip_m->del($id);
if ($this->db->affected_rows() > 0) {
echo "<script>alert('Data Berhasil dihapus'); </script>";
}
echo "<script>window.location='" . site_url('rekap') . "'; </script>";
}
VIEW
rekap_data.php
<div class="row">
<!-- DataTable with Hover -->
<div class="col-lg-12">
<div class="card mb-4">
<div class="card-header py-3 d-flex flex-row align-items-center justify-content-between">
<div class="col-md-4 offset-md-4">
<form id="form-filter">
<div class="form-horizontal">
<div class="form-group">
<div class="col-sm-9">
<div class="form-group">
<label for="bidang" class="col-sm-4 control-label">Bidang</label>
<?php echo $form_bidang; ?>
</div>
<div class="form-group">
<label for="skpd" class="col-sm-4 control-label">SKPD</label>
<input type="text" class="form-control" id="skpd">
</div>
<div class="form-group">
<label for="kode" class="col-sm-4 control-label">Kode</label>
<input type="text" class="form-control" id="kode">
</div>
<div class="form-group">
<label for="masalah" class="col-sm-4 control-label">Masalah</label>
<textarea class="form-control" id="masalah"></textarea>
</div>
<div class="form-group">
<button type="button" id="btn-filter" class="btn btn-primary">Filter</button>
<button type="button" id="btn-reset" class="btn btn-default">Reset</button>
</div>
</div>
</div>
</div>
</form>
</div>
</div>
<div class="table-responsive p-3">
<table class="table align-items-center table-flush table-hover" id="dataTableHover">
<thead class="thead-light">
<tr>
<th>#</th>
<th>Bidang</th>
<th>SKPD</th>
<th>Kode</th>
<th>Masalah</th>
<th>Nomor</th>
<th>Rincian</th>
<th>Tahun</th>
<th>Rak</th>
<th>Dos</th>
<th>Retensi</th>
<th>Keterangan</th>
</tr>
</thead>
<tbody>
</tbody>
</table>
</div>
</div>
</div>
</div>
<script type="text/javascript">
var table;
$(document).ready(function() {
table = $('#dataTableHover').DataTable({
"processing": true,
"serverSide": true,
"ajax": {
"url": "<?php echo site_url('rekap/ajax_list') ?>",
"type": "POST",
"data": function(data) {
data.id_bidang = $('#bidang').val();
data.skpd = $('#skpd').val();
data.kode = $('#kode').val();
data.masalah = $('#masalah').val();
}
},
"columnDefs": [{
"targets": [0],
"orderable": false,
}, ],
});
$('#btn-filter').click(function() {
table.ajax.reload();
});
$('#btn-reset').click(function() {
$('#form-filter')[0].reset();
table.ajax.reload();
});
});
</script>
the code above is the code that I use, there is no error but not working ... is there something wrong with my code, I ask for advice on what corrections if there are errors