Ref<PopulatedType, RawId>

Typings:

type Ref<
  PopulatedType,
  RawId extends mongoose.RefType = PopulatedType extends { _id?: mongoose.RefType }
    ? NonNullable<PopulatedType['_id']>
    : mongoose.Types.ObjectId
>

Parameters:

Name	Type	Description
`PopulatedType` Required	`object`	The Type of the what is expected when it is populated
`RawId`	`mongoose.RefType`	Overwrite the Reference type (the type of `_id` of `PopulatedType`)

The Type Ref<PopulatedType, RawId> is the type used for References.

PopulatedType: This is the Class being referenced.
RawId: This should be the _id Type of the referenced Class, by default its mongoose.Types.ObjectId and should get automatically inferred if a _id property is present on the target class.

There are typeguards to check if a reference is populated or of the reference type:

tip

For more and better explained examples, look at the Reference Other Classes Guide.

Example

Class to-be-referenced:

class Kitten {
  @prop()
  public name?: string;
}

Single Reference:

class Person {
  @prop({ ref: () => Kitten })
  public pet?: Ref<Kitten>;
}

Reference Array:

class Cat {
  @prop({ ref: () => Kitten })
  public babies?: Ref<Kitten>[];
}

Reference with different _id type:

class Kitten {
  @prop()
  public _id?: string;

  @prop()
  public name?: string;
}

// For Single References
class Person {
  // The "type" options in this case refers to the "_id" type of the referenced class, by default it will be "ObjectId"
  @prop({ ref: () => Kitten, type: () => String })
  public pet?: Ref<Kitten, string>;
}

// For a Array of References
class Person {
  // The "type" options in this case refers to the "_id" type of the referenced class, by default it will be "ObjectId"
  @prop({ ref: () => Kitten, type: () => String })
  public pet?: Ref<Kitten, string>[];
}

Example​

Example