即使表单验证失败，文件仍会通过multer上载

Question

我有一个添加产品的表格，该表格可以让用户输入产品名称，描述等，还可以上传图片。

在我的入口点app.js文件中，我有：

const fileStorage = multer.diskStorage({
    destination: (req, file, cb) => {
      cb(null, 'uploads');
    },
    filename: (req, file, cb) => {
       cb(null, new Date().toISOString() + '-' + file.originalname);
    }
  });


  const fileFilter = (req, file, cb) => {
    if (
      file.mimetype === 'image/png' ||
      file.mimetype === 'image/jpg' ||
      file.mimetype === 'image/jpeg'
    ) {
      cb(null, true);
    } else {
      cb(null, false);
    }
  };

app.use(multer({ storage: fileStorage , fileFilter: fileFilter, limits: { fileSize: 100000} }).single('image'));

这是我的控制人：

exports.postAddListing = (req, res, next) => {
    const title = req.body.title;
    const category = req.body.category;
    const description = req.body.description;
    const errors = validationResult(req);
    if (!errors.isEmpty()) {
        return res.status(422).render('account/add-listing', {
            pageTitle: 'Add Item',
            path: '/account/add-listing',
            errorMessage: errors.array(),
            successMessage: null,
            oldInput: {
                title: title,
                description: description
            }
        });
    }

    const image = req.file;
    const imageUrl = image.path;

    const product = new Product({
        title: title,
        category: category,
        description: description,
        userId: req.user,
        datePosted: Date.now(),
        imageUrl: imageUrl
    });
    product.save()
    .then(result => {
        const successMessage = req.flash('success', 'Item sucessfully added');
        res.redirect('/account/add-listing');
    })
    .catch(err => console.log(err));
};

我正在使用express-validator进行表单验证。我遇到的问题是，例如，如果我将所有字段都留空但选择一个图像，则会触发验证，并且会收到错误消息，但图像仍会上传。如果表单验证失败，我不想上传图片，但不确定如何实现。