Element-ui中 实现多选表格（Table）增加 ‘全选’ 字样

<template>
  <div class="test">
    <el-table
      ref="multipleTable"
      :data="tableData"
      :header-cell-style="{background:'#eef1f6',color:'#606266'}"
      size="mini"
      border
      stripe
      style="width: 50%"
      @selection-change="handleSelectionChange">
      <el-table-column align="center" type="selection" width="80"></el-table-column>
      <el-table-column align="center" label="日期" show-overflow-tooltip>
        <template slot-scope="scope">
          {{ scope.row.date }}
        </template>
      </el-table-column>
      <el-table-column align="center" prop="name" label="姓名" show-overflow-tooltip></el-table-column>
      <el-table-column align="center" prop="address" label="地址" width="450"></el-table-column>
    </el-table>
  </div>
</template>
<script>
export default {
  data() {
    return {
      tableData: [
        {
          date: '2016-05-03',
          name: '王小虎',
          address: '上海市普陀区金沙江路 1518 弄'
        },{
          date: '2016-05-02',
          name: '王小虎',
          address: '上海市普陀区金沙江路 1518 弄'
        },{
          date: '2016-05-04',
          name: '王小虎',
          address: '上海市普陀区金沙江路 1518 弄'
        },{
          date: '2016-05-01',
          name: '王小虎',
          address: '上海市普陀区金沙江路 1518 弄'
        },{
          date: '2016-05-08',
          name: '王小虎',
          address: '上海市普陀区金沙江路 1518 弄'
        },{
          date: '2016-05-06',
          name: '王小虎',
          address: '上海市普陀区金沙江路 1518 弄'
        },{
          date: '2016-05-07',
          name: '王小虎',
          address: '上海市普陀区金沙江路 1518 弄'
        }
      ],
      multipleSelection: []
    }
  },
  methods: {
    handleSelectionChange(val) {
      this.multipleSelection = val;
    }
  }
}
</script>
<style lang="stylus" scoped>
.test{
  ::v-deep .el-table__header .el-table-column--selection .cell .el-checkbox:after {
    color: #606266;
    content: "全选";
    font-size: 12px;
    margin-left: 2px;
    font-weight: bold;
  }
}
</style>