String to ObjectId automatic conversion - Mongodb

Describe the bug I use mikro-orm as part of an event storage system, sometimes an event sends a Payload containing an ObjectId like a string from another system. Mikro-orm automatically turns it into an ObjectId. This is a behavior that forces us to adapt our serialization.

To Reproduce I use:

@Entity()
export class DataContainer extends BaseEntity {

  constructor(data: any) {
    super();
    this.data = data;
  }

  @Property()
  data: any; // typing used to have some edge cases
}

The test:

test('do not automatically convert string to ObjectId in the all cases', async () => {
    const dataContainer = new DataContainer({
      partnerIdFromAnotherSystem: '0000007b5c9c61c332380f78',
    });

    expect(dataContainer.data.partnerIdFromAnotherSystem).toBe('0000007b5c9c61c332380f78');

    await orm.em.persistAndFlush(dataContainer);

    expect(dataContainer.data.partnerIdFromAnotherSystem).not.toBeInstanceOf(ObjectId);

    // need to clear to lost the original typing 'string'
    orm.em.clear();

    const getDataContainer = await orm.em.findOne(DataContainer, { id: dataContainer.id });
    expect(getDataContainer!.data.partnerIdFromAnotherSystem).not.toBeInstanceOf(ObjectId);
});

Expected behavior I don’t know what would be the best solution for this case. But it is an implicit behavior that cannot be customized.

Versions

Dependency	Version
node	12.13.0
typescript	3.6.5
mikro-orm	3.4.1
your-driver	mongodb

[B4nan]

will be fixed in v3.6.12

[iamomiid]

Here you can check this repository. I wonder how the test case is passing. Note: Use npm start to test.