Vue-Tables-2 Side Server Get Error " Cannot read property 'data' of undefined" Why?

Question

I am using vue-tables-2 for manage data. I wanna implement server side. But I got a problem. I can get the data as well. But I dont know why I got that error message. This is my code:

HTML

 <v-server-table :columns="columns" :options="options"></v-server-table>

Vue Js

<script>
var config = {
  "PMI-API-KEY": "erpepsimprpimaiy"
};
export default {
  name: "user-profile",
  data() {
    return {
      columns: ["golongan_name"],
      options: {
        requestFunction: function(data) {
          return this.$http({
            url: "api/v1/golongan_darah/get_all_data",
            method: "post",
            headers: config
          }).then(res => {
            this.data = res.data.data;
            console.log(res);
          });
        },
        filterable: ["golongan_name"],
        sortable: ["golongan_name"],
        filterByColumn: true,
        perPage: 3,
        pagination: { chunk: 10, dropdown: false },
        responseAdapter: function(resp) {
          return {
            data: resp.data,
            count: resp.total
          };
        }
      }
    };
  }
};
</script>

This is the error:

enter image description here