sortable issue in element-ui

To make sorting working, You need to pass key from data to prop ie prop="number" in el-table-column. For example. If you want to sorting Number column. You need to add prop="number" or any key you want to correspond to data in array which you are using for table

<el-table-column label="NO" prop="number" fixed width="100" sortable>    <template slot-scope="scope">{{scope.row.number}}</template></el-table-column>

And Full Solution to your code with another column sorting

<el-table v-loading="listLoading" :data="list">      <el-table-column type="selection" > </el-table-column>      <el-table-column label="NO" fixed width="100" prop="number" sortable><template slot-scope="scope">{{ scope.row.number }}</template></el-table-column>      <el-table-column v-for="head in formThead" :key="head.value" :prop="head.value" :label="head.title" :min-width="head.celwidth ==null ? 100: head.celwidth" :sortable="head.sortable">        <template slot-scope="scope">          {{ scope.row[head.value] }}        </template>      </el-table-column></el-table>