相关疑难解决方法(0)

如何在mongoose中保存编辑后的数据之前进行验证？

例如,如果sample.name数据库中已存在,则用户将收到某种错误,类似于此,这是我的代码,如下所示

//Post: /sample/edit
app.post(uri + '/edit', function (req, res, next) {
  Sample.findById(req.param('sid'), function (err, sample) {

    if (err) {
      return next(new Error(err));
    }

    if (!sample) {
      return next(new Error('Invalid reference to sample information'));
    }

    // basic info
    sample.name = req.body.supplier.name;
    sample.tin = req.body.supplier.tin;

    // contact info
    sample.contact.email = req.body.supplier.contact.email;
    sample.contact.mobile = req.body.supplier.contact.mobile;
    sample.contact.landline = req.body.supplier.contact.landline;
    sample.contact.fax = req.body.supplier.contact.fax;

    // address info
    sample.address.street = req.body.supplier.address.street;
    sample.address.city = req.body.supplier.address.city;
    sample.address.state = req.body.supplier.address.state;
    sample.address.country = req.body.supplier.address.country;
    sample.address.zip = req.body.supplier.address.zip;

    sample.save(function …

例如,如果我有这个架构

var userSchema = mongoose.Schema({
    username: String,
    email: String,
    password: String,
    _todo: [{ type: mongoose.Schema.Types.ObjectId, ref: 'Todo'}]
});

我希望用户名是唯一的密钥,其他用户无法复制.我怎样才能做到这一点？