今天讲下怎么给下拉框的值去重复

<el-select v-model="postData" style="width:220px;" multiple collapse-tags placeholder="请选择岗位">
        <el-option
          v-for="item in postOptions"
          :label="item.post_name"
          :value="item.post_name"
        />
      </el-select>

js：

var tempData =res.data.list;
var hash = {};
tempData = tempData.reduce(function (item, next) {
   hash[next.post_name] ? '' : hash[next.post_name] = true && item.push(next);
   return item;
}, []);
 self.postOptions = tempData;

ok~