elementui的el-table的全部展开和全部折叠

//orgalist是数据数组，this.$refs.tablerefresh表单对象
expandbtn() {
      this.expandall = !this.expandall //true
      console.log(this.expandall)
      this.orgalist.forEach((item, i) => {
        this.$refs.tablerefresh.toggleRowExpansion(item, this.expandall)
      })
      console.log(this.$refs.tablerefresh)
    },