vue踩坑记录之数组定义和赋值问题

<el-form-item label="有效日期"> <div class="block">  <el-date-picker   v-model="effective_date"   type="daterange"   range-separator="至"   start-placeholder="开始日期"   end-placeholder="结束日期">  </el-date-picker> </div></el-form-item>

data(){ return{  effective_date: [] }}

methods: { getContractInfo(){    this.service.hqStore.getContractList(this.$route.query.uid).then((res)=>{   let detail = res.datalist[this.$route.query.index];   this.effective_date[0] = this.stamptimeToDate(detail.valid_date);   this.effective_date[1] = this.stamptimeToDate(detail.invalid_date);  } }}

created(){   this.getContractInfo();   setTimeout(()=>{    console.log(this.effective_date);   })  },

this.effective_date = [this.stamptimeToDate(detail.valid_date),this.stamptimeToDate(detail.invalid_date)];