1.          exportData(val){
    2.          //初始化表格数据
    3.          this.tableData = val
    4.          this.dataIsReturn = true
    5.        },
    7. async fetchData(){
    8.          this.showFormData('export')
    9.         let res = await new Promise((resolve, reject) => {
    10.           //轮询
    11.         this.fetchDataTimer = setInterval(() => {
    12.              if(this.dataIsReturn){
    13.                this.fetchDataTimer = null
    14.                this.dataIsReturn = false
    15.                 resolve(true)
    16.              }
    17.            },1000)
    18.        })
    19.        return this.exportData
    20.       },