<span class="c-btn-link mr10" @click="beforeDate">前一天</span>
<el-date-picker
  v-model="valueDate"
  type="date"
  placeholder="选择日期"
  format="yyyy - MM - dd "
  value-format="yyyy - MM - dd"> <!--value-format="timestamp"为毫秒时间戳-->
</el-date-picker>
<span class="c-btn-link ml10" @click="afterDate">后一天</span>

mounted () {
  this.valueDate = new Date()
},
methods: {
  beforeDate () {
    this.valueDate = new Date(this.valueDate.setDate(this.valueDate.getDate() - 1))
  },
  afterDate () {
    this.valueDate = new Date(this.valueDate.setDate(this.valueDate.getDate() + 1))
  }
}

data () {
  return {
   
    valueDate: '',
    
  }
},