elementui之el-table-column日期格式显示方式

 <el-row>
            <el-table :data="tableData" style="width: 100%;">
                        <el-table-column prop="title" label="通知标题" >
                        </el-table-column>
                        <el-table-column prop="content" label="通知详情" >
                        </el-table-column>
                        <el-table-column prop="addTime" label="添加时间" :formatter="formatDate" >
                        </el-table-column>
                         <el-table-column prop="adminId" label="管理员ID" >
                        </el-table-column>
                        
                        <el-table-column label="操作">
                            <template slot-scope="scope">
                                <el-button type="primary" size="mini" @click="toEdit(scope)">编辑</el-button>
                                <el-button type="danger" size="mini" @click="deleteRole(scope)">删除</el-button>
                            </template>
                        </el-table-column>
                    </el-table>
                    <br>
                    <el-pagination
                        @size-change="handleSizeChange"
                        @current-change="handleCurrentChange"
                        :current-page="pagination.pageIndex"
                        :page-sizes="[5, 10, 20, 30, 40]"
                        :page-size=pagination.pageSize
                        layout="total, prev, pager, next"
                        :total=pagination.total>
                    </el-pagination>
        </el-row>

 //方法区
        formatDate(row, column) {
          // 获取单元格数据
          let data = row[column.property]
          if(data == null) {
              return null
          }
          let dt = new Date(data)
          return dt.getFullYear() + '-' + (dt.getMonth() + 1) + '-' + dt.getDate() + ' ' + dt.getHours() + ':' + dt.getMinutes() + ':' + dt.getSeconds()
        },