Custom loader accessor

[Adrinalin4ik]

• Added ability to use custom accessors for the loaders Now @GraphqlLoader can have foreignKey argument as a function. This function has 1 argument which is parent model.

  @GraphqlLoader({
  foreignKey: (parent: User) => parent.id
  })
  async tasks (
  @Loader() loader: LoaderData<TaskObjectType, number>
  ) {
  const tasks  = await this.taskRepository.createQueryBuilder('t')
      .where({
        assignee_id: In(loader.ids)
      }).getMany()
  
  return loader.helpers.mapOneToManyRelation(tasks, loader.ids, 'assignee_id');
  }

  It also toches polymorphic relations. For the polymorphic relations, polymorphic option can be a function which is providing access to the parent object and allow to select id and descriminator from it.

@ResolveField(() => [DescriptionableUnion], { nullable: true })
  @GraphqlLoader({
    polymorphic: (parent: DescriptionObjectType) => ({
      id: parent.description_id,
      descriminator: parent.description_type
    })
  })
  async descriptionable(
    @Loader() loader: PolymorphicLoaderData<[DescriptionText | DescriptionChecklist], number, DescriptionType>,
    @SelectedUnionTypes() types: SelectedUnionTypesResult
  ) {
    const results = [];

    for (const item of loader.polimorphicTypes) {
      switch(item.descriminator) {
        case DescriptionType.Text:
          const textDescriptions = await this.descriptionTextRepository.createQueryBuilder()
          .select(types.getFields(DescriptionTextObjectType))
          .where({
            id: In(item.ids)
          })
          .getRawMany();

          results.push({ descriminator: DescriptionType.Text, entities: textDescriptions })

          break;
        case DescriptionType.Checklist:
          const checklistDescriptions = await this.descriptionChecklistRepository.createQueryBuilder()
          .select(types.getFields(DescriptionChecklistObjectType))
          .where({
            id: In(item.ids)
          })
          .getRawMany();

          results.push({ descriminator: DescriptionType.Checklist, entities: checklistDescriptions })

          break;
        default: break;
      }
    }
    return loader.helpers.mapOneToManyPolymorphicRelation(results, loader.ids);
  }

All examples inside the code.