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="记录时间"

          prop="recordDateTime"

          :rules="[

            { required: true, message: '记录时间不能为空', 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>