element ui table插件的合并列

<el-table
                          :data="mTemList"
                          :span-method="objectSpanMethod"
                          border
                          style="width: 100%; margin-top: 20px">
                          <el-table-column
                            :prop="item.code"
                            :label="item.name"
                             v-for='item in tarArr' :key='item.code'>
                          </el-table-column>
                          
                    </el-table>

　　

 objectSpanMethod({ row, column, rowIndex, columnIndex }) {
    if (columnIndex === 0 || columnIndex === 1) {选择合并哪一列
          if (rowIndex % this.num === 0) {//合并多少行
            return {
              rowspan: this.num,  //要合并的行数
              colspan: 1
            };
          } else {
            return {
              rowspan: 0,
              colspan: 0
            };
          }
        }
        }