relations.ts

async loadRelationshipsForEntity(entity: BaseEntity, repo: Repository<any>, relationships: Array<string | [string, string[]]>) {

    // @ts-ignore
    const id = entity.id;

    const { ...res } = await Promise.all(
      relationships.map((relation) => {
        // @ts-ignore
        const relationsArray: string[] = Array.isArray(relation) ? [relation[0], ...relation[1].map(item => relation[0] + "." + item)] : [relation];

        return repo.findOne(
          {
            where: { id },
            select: ["id"],
            relations: relationsArray
          }
        );
      })
    );

    relationships.forEach((relation, i) => {
      const param = String(Array.isArray(relation) ? relation[0] : relation);
      entity[param] = res[i][param];
    });
  }

  async findOneGameById(id: number, platform?: Platform): Promise<Game | null> {

    const relationsExtended: Array<string | [string, string[]]> = [
      "gameStats",
      ["gamePlatforms", ["videos", "screenshots", "developer"]],
      ["gameTags", ["tag"]],
      ["gameCategories", ["category"]],
      "videoStreams"
    ];

    const game = await this.gameRepository.findOne({
      where: platform ? this.addPlatformToWhere(platform, { id }) : { id }
    });

    if (!game) return null;
    await this.loadRelationshipsForEntity(game, this.gameRepository, relationsExtended);
    return game;
  }