vue中使用element分批上传文件

<el-upload
          class="upload-demo"
          drag
          :auto-upload="true"
          action="#"
          multiple
          :limit="maxLen"
          :on-preview="onPreview"
          :on-change="handleChange"
          :on-success="handleVideoSuccess"
          :http-request="uploadSuccess"
          :on-remove="handleRemove"
          :on-exceed="handleExceed"
          :before-upload="beforeUploadVideo"
          :file-list="fileList"
          ref="upload"
        >
</el-upload>

//分批上传视频
      splitUpload(){
          let arr = [];
          let val = '';
          //每次最多同时上传5个文件
          while(arr.length < 5 && this.forUpload.length > 0){
            val = this.forUpload.shift();
            let formDataV = new FormData()
            formDataV.append('video', val.file)
            arr.push(material_uploadMaterialVideo_api(formDataV))
          }
          Promise.all(arr).then(arr=> {
            arr.forEach(res => {
              if (res.code == 1){
                this.uploadedFileList.push({"video_path":res.data.path,"name":val.file.name,"id":res.data.id});
              }else{
                this.$message({
                  message: res.sub_msg,
                  type: 'error'
                })
              }
            })
            if(this.forUpload.length > 0) this.splitUpload();
            else{
              this.loading = false;
              this.$message({
                  message: '视频上传成功',
                  type: 'success'
                })
            }
          })
      },
      //自动上传的方法
      uploadSuccess(val) {
          //调接口
          this.loading = true
          let formDataV = new FormData()
          formDataV.append('video', val.file)
          this.forUpload.push(val);
          //接收完列表的文件后开始分批上传
          if(this.forUpload.length == this.fileList.length){
            this.splitUpload();
          }
        }