vue3上传文件功能文件格式怎么写？

<input ref='uploadInput' type="file" class="dl-none" name="icon" @change="dealfilechange" />
        <CustomButton type="plain" color="color-primary" class="ml-2" @click="uploadgogo" >导入</CustomButton>

const dealfilechange = (e: Event) => {
  const input = e.target as HTMLInputElement;
  let files = input.files;
  if (files) {
    const formData=new FormData();
    formData.append(files[0].name,files[0])
      importfile(formData)
  }
}
const uploadgogo = ()=>{
            // console.log(uploadInput.value)
            let oBtn = uploadInput.value as HTMLInputElement;
            oBtn.click();
        }

发送参数后台返回是参数格式错误吗？应该怎么写？