how to reference nested documents in nestjs mongoose typescript

Question

I'm new with nestjs. I use @nestjs/mongoose and I need to reference several fields in a nested object in my class schema and I don't know how to do it.

The dietDays object must contain a date field and meals object that contain a 2 references to Meal schema.

What is the correct way to do it?

The code below shows how I tried to do it, as well as, the other way I tried was that create dietDays class and pass it to Prop type variable but in that scenario I am not able to reference to Meal schema because that was not a schema.

@Schema()
export class Diet {
  @Prop({ default: ObjectID })
  _id: ObjectID 

  @Prop()
  dietDays: [
    {
      date: string
      meals: {
        breakfast: { type: Types.ObjectId; ref: 'Meal' }
        lunch: { type: Types.ObjectId; ref: 'Meal' }
      }
    },
  ]
}

Answer 1

You should do it as following:

Create a class which refers to each day in the diet ( logically make sense )

@Schema()
export class DayInDiet {
  @Prop() date: string;
  @Prop()
  meals:
    {
        breakfast: { type: Types.ObjectId, ref: 'breakfast' }
        launch: { type: Types.ObjectId, ref: 'launch' }
    }
}

Knowing that each of which breakfast and lunch should be a valid mongo schemas.

If breakfast and lunch are not schemas, and you have a list of content you can pass this array as possible options for them inside the schema object.

Another possible way

@Schema()
export class DayInDiet {
  @Prop() date: string;
  @Prop()
  meals: [
     { type: Types.ObjectId, ref: 'meal' } // note that meal should be the name of your schema
  ]
}

@Schema()
export class Meal {
  @Prop() name: string;
  @Prop() type: 'launch' | 'breakfast'
}

simple note you are not required to make _id a prop of any schema

Edit

For the diet schema

@Schema()
export class Diet {
  // list of props
 // ...
  @Prop()
  dietDays: [
    { type: Types.ObjectId, ref: 'DayInDiet' }
  ]
}