What is the best way to validate updators using multiple fields upon calling findOneAndUpdate?

[richardnguyen99]

I have a Mongoose schema with NestJS:

@Schema({
  versionKey: false,
  id: false,
  collection: "basics",
  timestamps: false,
  toJSON: {
    virtuals: true,
  },
  toObject: {
    virtuals: true,
  },
})
export class BasicsModel extends mongoose.Document {
  // Other fields ...

  @Prop({ required: true, type: mongoose.Schema.Types.Number })
  startYear: number;

  @Prop({
    type: mongoose.Schema.Types.Number,
    default: null,
  })
  endYear: number | null;
}

I have an endpoint that allows callers to update a basic entity as following:

async updateByTconst(
  tconst: string,
  dto: BasicUpdateDto,
): Promise<BasicsModel | null> {
  return this.basicsModel
    .findOneAndUpdate(
      { tconst },
      { $set: dto },
      { new: true, runValidators: true },
    )
    .exec();
}

I want to make sure that endYear if not null is valid only if its value is greater than startYear.

I want to use Update validators to isolate my validations so this is what I came up with.

export const BasicsSchema = SchemaFactory.createForClass(BasicsModel);

BasicsSchema.path("endYear").validate(async function (value) {
  const existingBasic = await // @ts-ignore
  (this.mongooseCollection as unknown as mongoose.Model<BasicsModel>)
    // @ts-ignore
    .findOne(this._conditions);

  if (existingBasic) {
    if (value !== null && value < existingBasic.startYear) {
      throw new Error(
        "End year cannot be less than start year for existing basics.",
      );
    }
  }

  return true;
});

It works but it feels clunky and anti pattern because I have to use @ts-ignore and many evil type casting. Is there any better way to achieve what I want?

Here what I have tried:

• Using this.get("startYear") or this.startYear in my validator function does not work because both return undefined. In the case of this.get(), Mongoose states the following:

  However, when running update validators, this refers to the query object instead of the document. Because queries have a neat .get() function, you can get the updated value of the property you want.

  So basically, this.get("endYear") returns a value while this.get("startYear") does not.

• I avoid using pre hook middleware because I want to isolate the validations. You can assume that there are many more fields in the schema and there are multiple checks so I don't want to have a bloating hook. However, I'm opened to every argument that makes the hook function cleaner and more organized.