element-ui DatePicker 日期選擇器-讓結束日期大於開始日期

        <el-form-item label="起始日期" label-width="110px" prop="startDate">
          <el-date-picker
            v-model="ruleForm.startDate"
            type="date"
            placeholder="yyyy-mm-dd"
            class="limitWidth"
　　　　　　　:picker-options="pickerOptionsStart"
          ></el-date-picker>
        </el-form-item>
        <el-form-item label="結束日期" label-width="110px">
          <el-date-picker
            v-model="ruleForm.endDate"
            type="date"
            placeholder="yyyy-mm-dd"
            class="limitWidth"
 :picker-options="pickerOptionsEnd"
          ></el-date-picker>
        </el-form-item>

  data() {
    return {
      // 限制結束日期大於開始日期
      pickerOptionsStart: {
        disabledDate: time => {
          let endDateVal = this.ruleForm.endDate
          if (endDateVal) {
            return time.getTime() > new Date(endDateVal).getTime()
          }
        }
      },
      pickerOptionsEnd: {
        disabledDate: time => {
          let beginDateVal = this.ruleForm.startDate
          if (beginDateVal) {
            return time.getTime() < new Date(beginDateVal).getTime()
          }
        }
      },
      ruleForm: {
        startDate: '', // 開始日期
        endDate: '', // 結束日期
      }
    }
  }