vue+elementui el-table翻页后记录已勾选的数据

一、问题描述
当切换页码或者条数时，选中的数据会消失

二、翻页保留数据

给type为selection的el-table-column添加上reserve-selection属性

给el-table添加上:row-key="row => row.id"，id必须是唯一的

<el-table
       stripe
       size="mini"
       class="merit-table-tools-bottom"
       :data="tableData"
       :height="tableHeight"
       v-loading="loading"
       highlight-current-row
       element-loading-spinner="el-icon-loading"
       element-loading-background="rgba(255, 255, 255, 0.8)"
       @selection-change="handleSelectionChange"
       :header-cell-class-name="'merit-table-header'"
       :cell-class-name="'merit-table-row-normal'"
       :row-key="row => row.id"
   >
   <el-table-column type="selection" reserve-selection align="center" class-name="merit-table-column-normal"></el-table-column>