elementui custom table Total

// 表格合计
    heji(param){
      const {columns,data} = param
      const sums = [];
        columns.forEach((column, index) => {
          if (index === 0) {
            sums[index] = '合计';
            return;
          }
          const values = data.map(item => Number(item[column.property]));
          if (!values.every(value => isNaN(value))) {
            sums[index] = values.reduce((prev, curr) => {
              const value = Number(curr);
              if (!isNaN(value)) {
                return prev + curr;
              } else {
                return prev;
              }
            }, 0);
            if(column.label=='交易次数'){
              sums[index]=sums[index];
            }else{
              sums[index] = '￥'+sums[index];
            }
          } else {
            sums[index] = '/';
          }
        });
        return sums;
    }

Table bind method: summary-method 

elementui Address:  https://element.eleme.cn/#/zh-CN/component/table