element el-table 计算指定列

官网说明：将show-summary设置为true就会在表格尾部展示合计行。默认情况下，对于合计行，第一列不进行数据求合操作，而是显示「合计」二字（可通过sum-text配置），其余列会将本列所有数值进行求合操作，并显示出来。当然，你也可以定义自己的合计逻辑。使用summary-method并传入一个方法，返回一个数组，

    <el-table :data="distributionDetailList" border 
    :summary-method="getSummaries"
    show-summary
    >
        <el-table-column  type="index" prop="type" label="序号" width="50" align="center"></el-table-column>
        <el-table-column  label="业务线" prop="businessName"  align="center">
        </el-table-column>
        <el-table-column label="占比（业务线）" prop="businessProportion" align="center">
        </el-table-column>
        <el-table-column label="比例（部门）%" prop="departmentProportion" align="center">
        </el-table-column>
        <el-table-column label="部门" prop="departmentName" align="center">
        </el-table-column>
        <el-table-column label="职级" prop="rankName" align="center"></el-table-column>
        <el-table-column label="比例（职级）%" prop="rankProportion" align="center"></el-table-column>
        <el-table-column label="绝对值（职级）%" prop="rankMagnitude" align="center"></el-table-column>
    </el-table>

 methods: {
    		//指定列求和
	    	getSummaries(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 (column.property == 'businessProportion' ||column.property =='rankMagnitude' ) {
							sums[index] = values.reduce((prev, curr) => {
							 const value = Number(curr);
							 if (!isNaN(value)) {
							   return prev + curr;
							 } else {
							   return prev;
							 }
							}, 0);
							console.log(sums )
							sums[index];

				     }
				});
				return sums
	    	},
}