Solve the problem that element-ui table adds show-summary but the total is not displayed

1. Add the ref attribute to el-table

<el-table
　　ref="table1"
    border
　　size="mini"
　　show-summary >
</el-table>

2. In the updated life cycle function

updated () {
　　this.$nextTick(() => {
　　　　this.$refs['table1'].doLayout();
　　})
},