Vincit/Objection.js returns "cannot read property '$relation' of undefined" when using .withGraphFetched()

user_2639149 0
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I am currently setting up Objection.js with NestJS and am having trouble using any sort of graph fetch or save methods. Relevant models:

resource-group.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',
      },
    },
  }
}

attribute.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',
      },
    },
  }
}

resource-group.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});
  }
}

Anybody have any ideas of what's going on? I've looked through the source code but it appears to be an issue in my code, maybe in one of my models.

objection.js knex.js nestjs typescript
1 Answers

So I was stuck on this for a while, turned out to be something super simple. In resource-group.service.ts we need to make a slight change.

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

needs to become

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

Classic case of code-blindness but couldn't find a single hit on Google for my error message. Hopefully this will help someone who really needs a cup of coffee in the future (:

user_26391490
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