soal select2

<table class="table table-responsive" id="">
<tr>
                                    <th width="15%">Pegawai</th> <td width="5%"><center>:</center></td>
                                <td><input  placeholder="pilih id karyawan" class="form-control"
                                            name='id_karyawan' id='id_karyawan' /> </td>
                                </tr>
                                <!--

                                    'company_name',
                                );
                                -->
                                <tr>
                                    <th>Employee NIK</th>
                                    <td width="5%"><center>:</center></td>
                                <td>
                                    <input type="text" placeholder="989898999"
                                           id='emp_nik' name='emp_nik' class="form-control"></td>
                                </tr>
                                <tr>
                                    <th>Employee Name</th>
                                    <td width="5%"><center>:</center></td>
                                <td><input type="text" placeholder="Nama Pegawai"
                                           id='emp_name' name='emp_name'  class="form-control"></td>
                                </tr>
</table>

<script> var _select2_URL='tujuan';</script>
<script>
$('#id_karyawan').select2({
    placeholder: 'Pilih Karyawan',
    minimumInputLength: 3,
    ajax: {
        url: _select2_URL,
        data: function (params) {
            console.log(params);
            var query = {
                search: params,
                type: 'public'
            }
            return query;
        },
        dataType: 'json',

        delay: 250,

        processResults: function (data) {
            return {
                results: data
            };
        },
        cache: true

    },
    formatSelection: function (dt) {
        return dt.text  + ' (' + element.id + ')';
    },
    formatResult: function (element) {
        return element.text;
    }

});
</script>

<!--- target JSON nya --->
<?php
$json = array();
    //memakai karyawan
    $this->load->model('main/karyawan_model','karyawan');
    $users=array(
        array('id'=>1,'title'=>'Hadi','nik'=>534324324),
        array('id'=>2,'title'=>'Daniel','nik'=>25324324),
        array('id'=>3,'title'=>'Garren','nik'=>64324324),
    );

foreach($users as $row){
$json[] = [
         'id'=>$row['id'],
         'text'=>$row['title']. " (NIK: ".$row['nik'].")",
         'raw'=>$row
         ];

    }


    echo json_encode($json);