[Discussion] Mongoose schema hooks w/ dependency injection about mongoose

[kamilmysliwiec]

There is currently no way to add mongoose schema hooks that depend on any @Injectable() services using the nest MongooseModule.

Actually, why not? You should be able to create, let's say, SchemaHooks class that would inject schema + all required services and register hooks in onModuleInit() lifecycle method.

@kamilmysliwiec Could you possibly provide an example of that? As far as I can see you cannot register schema hooks after connection.model() is called, which the MongooseModule does in its providers factory.

[kamilmysliwiec]

Oh well, it seems that this behavior has changed between 4.x.x -> 5.x.x releases. In this case, you can avoid using .forFeature() and create providers manually:

{
      provide: getModelToken('Cat'),
      useFactory: (connection) => {
           const schema = ...
           // add hooks here
          return connection.model('Cat', schema);
      },
      inject: [getConnectionToken('YOUR_CONNECTION_NAME')],
},

[jselesan]

@kamilmysliwiec sorry to ask on a closed issue. I'm trying to create my providers manually as you posted here, but I get a ** Nest can't resolve dependencies of the useFactory (?). Please verify whether [0] argument is available in the current context.**

This is my code on the test:

        let catModel;
        const module = await Test.createTestingModule({
            providers: [
                CatsService,
                {
                    provide: getModelToken('Cat'),
                    useFactory: (connection) => {
                        catModel = connection.model('Cat', CatSchema);
                        return catModel;
                    },
                    inject: [getConnectionToken('MyDatabase')]
                }
            ]
        }).compile();

and my service looks like this:

@Injectable()
export class CatsService {
  constructor(@InjectModel('Cat') private readonly catModel: Model<Cat>) {}

  async create(createCatDto: CreateCatDto): Promise<Cat> {
    const createdCat = new this.catModel(createCatDto);
    return await createdCat.save();
  }

  async findAll(): Promise<Cat[]> {
    return await this.catModel.find().exec();
  }
}

What am I doing wrong?