js-時間変換

    //    
    timestampToTime(timestamp) {
      var date = new Date(timestamp);
      this.birthday =
        date.getFullYear() + "-" + (date.getMonth() + 1) + "-" + date.getDate();
    },

      <van-datetime-picker
        v-model="currentDate"
        type="date"
        :min-date="minDate"
        :max-date="maxDate"
        @confirm="confirm"
        @cancel="cancel"
      />