请教一下 以下错误怎么去解决呢？

错误信息 { [Error: EISDIR, open '/Volumes/mac/nodeProject/demo1/public/images/'] errno: 28, code: 'EISDIR', path: '/Volumes/mac/nodeProject/demo1/public/images/' }

我的代码

var target_path = __dirname +'/public/images/';

fs.readFile(req.files.Imgfile.path, function (err, data) {
                     console.log(target_path);
    fs.writeFile(target_path, data, function (err) {
        console.log(err);
        res.redirect("back");
        res.send("ok");
    });
});