Date input verification element-ui

validateDate(rule, value, callback){
     if (value) {       
       let timestamp = new Date(value).getTime()
       let start  = new Date(this.shiftStartTime).getTime()
       let end = new Date(this.shiftEndTime).getTime()
       if (end < timestamp || timestamp < start) {
         callback(new Error(`请在值班时间内选择  ${this.shiftStartTime} 至 ${this.shiftEndTime}`))
       } else {
         callback()
       }
     } else {
       callback()
     }
   },

<EL-form- Item 
          label = " recording time " 
          prop = " recordDateTime " 
          : the rules = " [ 
            {required: to true , Message: ' recording time can not be empty ' , Trigger: ' Blur ' }, 
            {Validator: validateDate, Trigger : [ ' Blur ' , ' Change ' ]} 
          ] "
         > 
          <el-date-picker
            v-model="summaryForm.recordDateTime"
            type="datetime"
            value-format="yyyy-MM-dd HH:mm:ss"
            placeholder="选择日期"
          ></el-date-picker>
        </el-form-item>