vant框架 日历组件格式化

项目开发发现，日历组件的值直接传到后端会报400，需要将时间格式化才行,话不多说直接上代码

<van-field
  readonly
  clickable
  name="date"
  :value="detailInfo.calendar"
  label="日期"
  placeholder="点击选择日期"
  @click="showCalendar = true"
/>
<van-calendar v-model="showCalendar" @confirm="onConfirmCalendar" />
onConfirmCalendar(value,index){
      let date = new Date(value)
      let y = date.getFullYear()
      let m = date.getMonth() + 1
      m = m < 10 ? ('0' + m) : m
      let d = date.getDate()
      d = d < 10 ? ('0' + d) : d
      const time =  y + '-' + m + '-' + d;
      console.log(time)//输出例：2021-06-23
      this.detailInfo.calendar = time;
      this.showCalendar = false;
    }