Typescript TypeORM findOneBy({id: id}) fails in generic abstract class

Question

I am using "typeorm": "^0.3.7".

import { IRepository, EntityBase } from "core"
import { Database } from "../../db"
import { EntityTarget, Repository } from "typeorm"
export abstract class RepositoryBase<T extends EntityBase> implements IRepository<T> {
    protected _repository: Repository<T>;
    constructor(entity: EntityTarget<T>) {
        this._repository = Database.AppDataSource.getRepository(entity);
    }
    public async GetById (id: number): Promise<T | null> {
        return await this._repository.findOneOrFail({
            where: { id: id },
            relations: ["teachers"]
        });
    }
}

fails:

error TS2322: Type '{ id: number; }' is not assignable to type 'FindOptionsWhere<T> | FindOptionsWhere<T>[] | undefined'.

EntityBase.ts:

import { Entity, PrimaryGeneratedColumn, Column, BaseEntity } from "typeorm"
@Entity()
export abstract class EntityBase extends BaseEntity {
    @PrimaryGeneratedColumn()
    public id: number
    @Column()
    public created: Date
    @Column()
    public modified: Date
    constructor() {
        super();
        this.created = new Date();
    }
}

Student.ts entity:

import { Entity, PrimaryGeneratedColumn, Column } from "typeorm"
import { EntityBase } from "./EntityBase"
@Entity()
export class Student extends EntityBase {
    @Column()
    public firstName: string

    @Column()
    public lastName: string

    @Column({ unique: true })
    public email: string

    @Column()
    public isSuspended: Boolean

    @ManyToMany((type) => Teacher, (teacher) => teacher.students)
    @JoinTable()
    public teachers: Teacher[]

    constructor(first: string, last: string, email: string, isSuspended?: boolean) {
        super();
        this.firstName = first;
        this.lastName = last;
        this.email = email;
        this.isSuspended = isSuspended ?? false;
    }
}

Using findOneBy({id: id}) in concrete class is OK. Any though on that?

I think you'll have to use the "where" key here. Something like findOneByOrFail({ where: { id: id } }). Alternatively for findOne functions if I remember correctly if you're finding by the primary key then simply findOneByOrFail(id) might work too. ref: https://typeorm.io/find-options — long_hair_programmer, Aug 13 '22 at 07:26
Can you update the question with code of Student entity class and repository? — long_hair_programmer, Aug 13 '22 at 08:41
Thanks. I assume "id" is in EntityBase class. Does it have Column or PrimaryGeneratedColumn decorator on it? If not you'll have to add the id field along with the desired decorator in Student class — long_hair_programmer, Aug 13 '22 at 09:00

long_hair_programmer · Answer 1 · 2022-08-13T16:38:52.300

In the StudentRepository we don't need to add the generic type variables in <>. Essentially you want to extend the RepositoryBase with Student type so this will work

export class StudentRepository extends RepositoryBase<Student> {
    constructor() {
        super(Student);
    }

    public override async GetById (id: number): Promise<Student | null> {
        return this._repository.findOneByOrFail({ id });
    }
}

Writing StudentRepository<Student extends EntityBase> makes it generic as well - it's the same as writing T (or anything else) rather than Student.

Hope this solves it for you as well!

PS just a side note: await keyword isn't required when returning from an async function unless it's in a try..catch as explained here

Yes, I missed that one. Good catch. It's still an open issue: https://github.com/typeorm/typeorm/issues/8939 — Kok How Teh, Aug 14 '22 at 00:49

Typescript TypeORM findOneBy({id: id}) fails in generic abstract class

1 Answers1