这是我的Multer配置文件

module.exports = (multer({
    storage: multer.diskStorage({
        destination: (req, file, cb) => {
            cb(null, './public/upload/especies')
        },
        filename: (req, file, cb) => {
            cb(null, Date.now().toString() + "_" + file.originalname)
        }
    }),
    fileFilter: function (req, file, cb) {
        if (!file.originalname.match(/\.(jpg|jpeg|png)$/)) {
            console.log('false')
            return cb(null, false);
        }
        console.log('true')
        return cb(null, true);
    }
}))

然后我调用这个文件config作为上传图像路由器内部的中间件

const router = express.Router();
const uploadImg = require("../middlewares/UploadImageEspecie");
router.post("/uploadImg", uploadImg.array('images', 12), async (req, res) => {
    if (req.files) {
        console.log(req.files)
        return res.json({
            error: false,
            message: "Upload realizado com sucesso!"
        })
    }
    else {
        return res.status(400).json({
            error: true,
            message: 'Erro: Upload não realizado com sucesso, necessário enviar imagens no formato PNG, JPG ou JPEG.'
        })
    }
});
module.exports = router;

但是，由于某种原因，当我尝试上传一些.mp4或.psd扩展名的文件时，它不会返回错误404状态，并且还会打印console.log false。为什么会这样？