Change _id Type

You can easily change the type of the _id field by doing:

class SomeChangedID {
  @prop()
  public _id!: string; // change the type of _id to string
}

The example above sets the _id type to be a string, but does not provide a default function, so the _id property needs to be always set manually before saving / inserting a document, use the default option to set a function to generate a new id automatically, be careful to not forget that using default: fn() will only call the function once at scope time instead of everytime a new document is created.

class SomeUUIDv4 {
  @prop({ required: true, default: () => uuidv4() })
  public _id!: string;
}

The _id property can also be disabled for subdocuments, with the prop option _id: false for the field in the class that uses the subdocument, or the schema option _id, but note that the schema-option does not disable _id if it is not a sub-document.

@modelOptions({ schemaOptions: { _id: false } }) // with the schema option
class WithNoId {
  @prop()
  public someValue: string;
}

class SomeChangedID {
  @prop({ type: WithNoId, _id: false }) // or with the prop-option
  public someField: WithNoId[];
}

With the Base Interface

There is also a Base interface typegoose provides which includes _id and id, it can be used as follows:

class Something implements Base<string> {
  @prop()
  public _id: string;
  // .. other properties "Base" might provide and needs to be implemented
}

// The Base interface can also be used together with other classes and other interfaces
class Something extends TimeStamps implements Base<string> {
  @prop()
  public _id: string;
  // .. other properties "Base" might provide and needs to be implemented
}

Restriction

This method (extending Base) can only be used with types that are in RefType (all of mongoose.Schema.Types should work except Array, Mixed, Boolean).