Initializing mongo ref as string instead of ObjectId

Bug Report

Accordingly to the docs

In case you want to specify relation to another model, later for populating, you can use @Prop() decorator as well. For example, if Cat has Owner which is stored in a different collection called owners, the property should have type and ref. For example:

import { Types } from 'mongoose';
import { Owner } from '../owners/schemas/owner.schema';

@Prop({ type: Types.ObjectId, ref: Owner.name })
owner: Owner;

So, I tried it…

Current behavior

Mongo is storing targetUser as an string

{
  "_id" : ObjectId("5fb2999b0b7d61a62cdc88b8"),
  "targetUser" : "5faf0044ddfbfd93d02f6714",
  "__v" : 0
}

Input Code

import { User } from "@/user/schemas/user.schema";
import { Prop, Schema } from "@nestjs/mongoose";
import { IsMongoId, IsOptional, IsString } from "class-validator";
import { Types } from "mongoose";

@Schema({ timestamps: true })
export default class NotificationDto {
  @IsString()
  @IsMongoId()
  @IsOptional()
  @Prop({ type: Types.ObjectId, ref: User.name })
  targetUser?: User;
}

// controller
@Post()
async create(
  @Body() notificationDto: NotificationDto,
): Promise<NotificationDto> {
  const notification = await this.notyService.create(notificationDto);
  return notification.toJSON();
}

// service
create(notification: NotificationDto): Promise<NotificationDocument> {
  return this.notificationModel.create(notification);
}

// request payload
{
  "targetUser": "5faf0044ddfbfd93d02f6714"
}

Expected behavior

Mongo should store targetUser as an ObjectId:

{
  "_id" : ObjectId("5fb2999b0b7d61a62cdc88b8"),
  "targetUser" : ObjectId("5faf0044ddfbfd93d02f6714"),
  "__v" : 0
}

Environment

Nest version: 7.5.1
 
For Tooling issues:
- Node version: 12.19.0
- Platform:
  $ cat /etc/os-release  
  NAME="Ubuntu"
  VERSION="20.04.1 LTS (Focal Fossa)"
  ID=ubuntu
  ID_LIKE=debian
  PRETTY_NAME="Ubuntu 20.04.1 LTS"
  VERSION_ID="20.04"
  HOME_URL="https://www.ubuntu.com/"
  SUPPORT_URL="https://help.ubuntu.com/"
  BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
  PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
  VERSION_CODENAME=focal
  UBUNTU_CODENAME=focal


Others:

[michal]

@Pacheco95 try mongoose.Schema.Types.ObjectId instead of mongoose.Types.ObjectId, 2nd one works only with arrays - something like this @Prop({ type: [{ type: Types.ObjectId, ref: User.name }] })

[Rush]

I just tried using a field that point to a document from a different collection and also had issues. Also in my use case I sometimes have ObjectId and sometime populate. So shouldn’t the examples give the following?

@Prop({ type: Schema.Types.ObjectId, ref: Owner.name })
owner: Owner | Types.ObjectId;

When a user forgets to populate the types should indicate it’s an ObjectId