问对象存储上传图片后，回调函数被调用两次？

function uploadPic() {
   console.log("update");
   let imgInput = $("input[name='files']");
   let file = imgInput[0].files[0];
   if (file === undefined ) {
      console.log("get file error")
      return false;
   }
   let fileName = new Date().getTime() + getRandom(6);
   cos.putObject({
      Bucket: tencentCosBucket, /* 必须 */
      Region: 'ap-beijing',     /* 存储桶所在地域，必须字段 */
      Key: fileName,              /* 必须 */
      StorageClass: 'STANDARD',
      Body: file, // 上传文件对象
      onProgress: function(progressData) {
         console.log("response");
         let url = tencentCosViewUrl + fileName;
         let html = "<em><img src=\"" + url + "\" alt=\"\"><i onclick='remove(this)'>x</i></em>";
         $(".em_img").append(html);
      }
   }, function(err, data) {
      console.log(err || data);
   });
}