el-select加上搜索查询时，限制开头空格输入

**1、注释：**结构中的ref和@input.native很重要

<el-form-item label="商品类型：" prop="productType">
   <el-select
     ref="eleSelect" //这里很重要1
     v-model.trim="formData.productType"
     placeholder="请选择"
     filterable
     clearable
     @input.native="trimSelect"  //这里很重要2
   >
     <el-option
       v-for="item in dictList.SPLX"
       :key="item.dictId"
       :label="item.dictLabel"
       :value="item.dictValue"
     ></el-option>
     
 </el-select>
</el-form-item>

2、js中限制开头为空格时重新赋值为空

  // 开头为空格时重新赋值为空
  const eleSelect = ref()
  const trimSelect = ()=>{
    let regex = /^\s*$/;
    if(regex.test(eleSelect.value.selectedLabel)){
       eleSelect.value.selectedLabel = ''
    }
  }