element-ui 自定義 Upload 上傳進度條

<el-upload
   class="upload-demo"
   ref="vidos"
   :action="URL+'/api/post/file'"
   :data="date"
   :on-success="handleAvatarAUDIO"
   :before-upload="beforeAvatarAUDIO"
   :on-progress="beforeAvatarUpload" //需要用到此方法
   accept=".mp4"
   :auto-upload="vidoauto"
   :on-change="AvatarAUDIO"
  :file-list="fileList"
 >

beforeAvatarUpload(event, file, fileList){
   let loadProgress = Math.floor(event.percent) //這就是當前上傳的進度
   //可以進行其他邏輯
 },