I have defined a DTO and configured it as follows to use common properties in multiple places.

// base-brand.dto.ts
import { ApiProperty } from '@nestjs/swagger';

export class BaseBrandDto {
 @ApiProperty({
  type: Number,
  required: true,
  example: 1,
 })
 readonly id: number;

 @ApiProperty({
  type: String,
  required: true,
  example: 'Default',
 })
 readonly name: string;
}

// game-brand.dto.ts
import { ApiProperty, PickType } from '@nestjs/swagger';
import { BaseBrandDto } from './base/base-brand.dto';

export class GameBrandDto extends PickType(BaseBrandDto, ['id', 'name'] as const) {
 @ApiProperty({
  example: 'EA',
 })
 readonly name: string;
}

// find-all-game-brands.dto.ts
import { ApiProperty, PickType } from '@nestjs/swagger';
import { ValidateNested } from 'class-validator';
import { Type } from 'class-transformer';
import { GameBrandDto } from './game-brand.dto.ts';

class GameBrandListsDto {
 @ValidateNested({ each : true })
 @Type(() => GameBrandDto)
 @ApiProperty({
  type: [GameBrandDto],
  required: true,
  examples: [GameBrandDto],
 })
 readonly lists: GameBrandDto[];
}

export class FindAllGameBrandsDto extends PickType(BaseResponseDto, ['result', 'message'] as a const) {
 @ValidatedNested({ each : true })
 @Type(() => GameBrandListsDto)
 @ApiProperty({
  type: GameBrandListsDto,
  required: true,
  example: GameBrandListsDto,
 })
 readonly brand: GameBrandListsDto;
}

This form doesn’t present any issues in the NestJS CLI. However, accessing the Swagger documentation causes a console error

Uncaught ReferenceError: _swagger is not defined”

It suggests that there is an issue with init, showing the following error line.

“GameBrandListsDto”: {
          “type”: “object”,
          “properties”: {
            “lists”: {
              “examples”: [
                class GameBrandDto extends (0, _swagger.PickType)(_basebranddto.BaseBrandDto, [
    'id',
    'name'
])

What seems to be the problem?