使用 .withGraphFetched() 时，Vincit/Objection.js 返回“无法读取未定义的属性‘$relation’”

Question

我目前正在使用 NestJS 设置 Objection.js，但在使用任何类型的图形获取或保存方法时遇到问题。相关型号：

资源组.model.ts

import { BaseModel } from './base.model';
import { Model } from 'objection';
import { ResourceGroupTypeModel } from './resource-group-type.model';
import { CollectionModel } from './collection.model';
import { AttributeModel } from './attribute.model';
import { ResourceModel } from './resource.model';

export class ResourceGroupModel extends BaseModel {
  static tableName = 'resource_group';

  typeId: number;
  title: string;
  groupId: string;
  collectionId?: number;
  defaultResourceId?: number;
  isDeleted: boolean;

  static relationMappings = {
    attributes: {
      modelClass: AttributeModel,
      relation: Model.ManyToManyRelation,
      join: {
        from: 'resource_group.id',
        through: {
          from: 'resourcegroup_attribute.resource_group_id',
          to: 'resourcegroup_attribute.attribute_id'
        },
        to: 'attribute.id',
      },
    },
  }
}

属性.model.ts

import { BaseModel } from './base.model';
import { Model } from 'objection';

export class AttributeModel extends BaseModel {
  static tableName = 'attribute'

  name: string;
  value: string;
  isSystem: boolean;

  static relationMappings = {
    resourceGroups: {
      modelClass: `${__dirname}/resource-group.model.js`,
      relation: Model.ManyToManyRelation,
      join: {
        from: 'attribute.id',
        through: {
          from: 'resourcegroup_attribute.attribute_id',
          to: 'resourcegroup_attribute.resource_group_id',
        },
        to: 'resource_group.id',
      },
    },
  }
}

资源组.service.ts

import { Injectable, Inject } from '@nestjs/common';
import { InjectRepository } from '@nestjs/typeorm';
import { EntityService } from '../abstract';
import { ResourceGroup } from '../entities';
import { Repository } from 'typeorm';
import { ModelClass } from 'objection';
import { ResourceGroupModel } from '../db/models/resource-group.model';

@Injectable()
export class ResourceGroupService extends EntityService<ResourceGroup> {
  constructor(
    @InjectRepository(ResourceGroup)
    protected readonly repository: Repository<ResourceGroup>,
    @Inject(ResourceGroupModel)
    protected readonly model: ModelClass<ResourceGroupModel>,
  ) {
    super(repository);
  }

  test() {
    return this.model
      .query()
      // .findById(25);                 // this line works fine

      .withGraphFetched(['attributes']) // these two lines do not
      .where({id: 25});
  }
}

有人对发生的事情有任何想法吗？我查看了源代码，但这似乎是我的代码中的一个问题，也许是我的一个模型中的问题。

Answer 1

所以我在这个问题上停留了一段时间，结果发现这是非常简单的事情。我们resource-group.service.ts需要做一些小小的改变。

    return this.model
      .query()
      .withGraphFetched(['attributes'])
      .where({id: 25});

需要成为

    return this.model
      .query()
      .withGraphFetched('[attributes]') // square brackets are inside the string itself
      .where({id: 25});

代码盲的典型案例，但在 Google 上找不到我的错误消息的任何点击。希望这对将来真正需要一杯咖啡的人有所帮助（：