让Vuetify v-data-table列首先按降序排序，然后按升序排序？

<template>
  <v-data-table
    :headers="headers"
    :items="items"
    :sort-by="sortBy"
    :sort-desc="sortDesc"
    @click:header="sortTable"
  ></v-data-table>
</template>

<script>
export default {
  data() {
    return {
      headers: [
        { text: 'Name', value: 'name', sortable: true },
        { text: 'Age', value: 'age', sortable: true },
        { text: 'Gender', value: 'gender', sortable: true },
      ],
      items: [
        { name: 'John', age: 25, gender: 'Male' },
        { name: 'Alice', age: 30, gender: 'Female' },
        { name: 'Bob', age: 20, gender: 'Male' },
      ],
      sortBy: 'name',
      sortDesc: true,
    };
  },
  methods: {
    sortTable(column) {
      if (column.sortable) {
        if (this.sortBy === column.value) {
          this.sortDesc = !this.sortDesc;
        } else {
          this.sortBy = column.value;
          this.sortDesc = true;
        }
      }
    },
  },
};
</script>