Self-Referencing ManyToMany Relationship TypeORM

Question

I have just started using TypeORM and I\'m struggling getting the following relationship to work:

User->Friends, whereas a Friend is also a User Object. My getters, getF

Answer 1

You can self-reference your relations. Here is an example of a simple directed graph (aka a node can have a parent and multiple children).

@Entity()
export class Service extends BaseEntity {

  @PrimaryGeneratedColumn()
  id: number;
  
  @Column()
  @Index({ unique: true })
  title: string;

  @ManyToOne(type => Service, service => service.children)
  parent: Service;

  @OneToMany(type => Service, service => service.parent)
  children: Service[];
}

An important note to keep in mind is that these relations are not auto loaded when reading an object from the DB with find* functions.

To actually load them, you have to use query builder at the moment and join them. (You can join multiple levels.) An example:

let allServices = await this.repository.createQueryBuilder('category')
  .andWhere('category.price IS NULL')
  .innerJoinAndSelect('category.children', 'product')
  .leftJoinAndSelect('product.children', 'addon')
  .getMany();

Please note how I used different names to reference them (category, product, and addon).