Element Upload上传校验失败后强制删除上传列表中校验失败的那一项

<el-upload 
    ref="uploadCpRef" 
    action="#" 
    list-type="picture-card" 
    :auto-upload="false" 
    :on-change="cpImgChange"
    :file-list="tableData.cpMainImg">
</el-upload>

关键代码：this.$refs.XXX.uploadFiles.splice(this.$refs.XXX.uploadFiles.indexOf(), 1);

cpImgChange(file, fileList){
  const isIMG = ['jpeg', 'png', 'gif', 'jpg'].includes(file.raw.type.split('/')[1]);
  if (!isIMG) {
    this.$refs.uploadCpRef.uploadFiles.splice(this.$refs.uploadCpRef.uploadFiles.indexOf(), 1);
    this.$message.error('上传图片只能是jpeg/png/gif/jpg格式!');
  }
},

注：本人前端小白 ，如有不对的地方还请多多指教