API with NestJS #67. Migrating to TypeORM 0.3

July 11, 2022

This entry is part 67 of 180 in the API with NestJS

For a long time, TypeORM seemed to have a reputation of being somewhat stagnant. Lately, they stepped up their game, though, and started releasing many new versions. When doing that, they introduced a large number of breaking changes. In this article, we go through the most significant differences between 0.2.x and 0.3.x versions so far and see how they affect NestJS projects.

When writing this article, I was using TypeORM 0.3.7 and @nestjs/typeorm 8.1.4

Changes made to the repository API

TypeORM made a few changes to the functions we use to query the data.

Changes to the findOne method

First, they got rid of the findOne() function returning the first row from the table when not provided with an argument. It was caused by findOne(undefined) being confusing.

What’s more, TypeORM dropped the support for using findOne(id) to make the syntax more consistent. So now, we can only use findOne() by providing it with an object.

Because of all of the above, the following code no longer works:

this.categoriesRepository.findOne(

id,

{

relations: ['posts'],

withDeleted: true

}

);

error TS2554: Expected 1 arguments, but got 2.

Instead, we must pass a single object to the findOne() method.

this.categoriesRepository.findOne(

{

where: {

relations: ['posts'],

withDeleted: true

}

);

To see all of the available options, check out the FindOneOptions interface.

Although the above code with relations: ['posts'] still works, it is now deprecated and will soon be removed. Instead, we should use a new object-literal notation.

this.categoriesRepository.findOne(

{

where: {

relations: {

posts: true

withDeleted: true

}

);

If we want to load a nested relation, we can create an object like this one:

relations: {

posts: {

author: true

}

Changes to the find method

TypeORM made a similar set of changes to the find() method. Because of that, the following code is no longer valid:

this.commentsRepository.find({

post: {

id: query.postId

}

});

error TS2345: Argument of type { post: { id: number; }; } is not assignable to parameter of type FindManyOptions<Comment>.

Instead, we need to provide the where object explicitly.

this.commentsRepository.find({

where: {

post: {

id: query.postId

}

});

Besides the findOne and find methods, similar changes happened to findOneOrFail, count, and findAndCount.

Using the new findOneBy and findBy functions

When querying data, we don’t always need additional options, such as relations. In that case, we can use the new findOneBy method.

this.databaseFilesRepository.findOneBy({

id: fileId

});

Similarly, we can use the new findBy method if we want to find multiple entities and don’t need to provide additional options such as relations.

this.commentsRepository.findBy({

post: {

id: query.postId

}

});

Besides the above, we also have new findOneByOrFail, countBy, and findAndCountBy functions.

Deprecating the findByIds method

The findByIds is now deprecated and will soon be removed. Instead, we can use the findBy method with the In operator.

import { In } from 'typeorm';

postsRepository.findBy({

id: In([1, 2, 3])

})

Renaming Connection to DataSource

Before TypeORM 0.3.0, the configuration with our database used to be called a Connection. Recently, TypeORM renamed it to DataSource.

Throughout this series, we didn’t interact with the Connection much except for working with transactions.

users.service.ts

import { Injectable, InternalServerErrorException } from '@nestjs/common';

import { InjectRepository } from '@nestjs/typeorm';

import { Repository, Connection } from 'typeorm';

import User from './user.entity';

import { FilesService } from '../files/files.service';

@Injectable()

export class UsersService {

constructor(

@InjectRepository(User)

private usersRepository: Repository<User>,

private readonly filesService: FilesService,

private connection: Connection

) {}

async deleteAvatar(userId: number) {

const queryRunner = this.connection.createQueryRunner();

const user = await this.getById(userId);

const fileId = user.avatar?.id;

if (fileId) {

await queryRunner.connect();

await queryRunner.startTransaction();

try {

await queryRunner.manager.update(User, userId, {

...user,

avatar: null

});

await this.filesService.deletePublicFileWithQueryRunner(fileId, queryRunner);

await queryRunner.commitTransaction();

} catch (error) {

await queryRunner.rollbackTransaction();

throw new InternalServerErrorException();

} finally {

await queryRunner.release();

}

// ...

}

Unfortunately, the above code is no longer valid. Instead of Connection, we should use DataSource instead.

users.service.ts

import { Injectable, InternalServerErrorException } from '@nestjs/common';

import { InjectRepository } from '@nestjs/typeorm';

import { Repository, DataSource } from 'typeorm';

import User from './user.entity';

import { FilesService } from '../files/files.service';

@Injectable()

export class UsersService {

constructor(

@InjectRepository(User)

private usersRepository: Repository<User>,

private readonly filesService: FilesService,

private dataSource: DataSource

) {}

async deleteAvatar(userId: number) {

const queryRunner = this.dataSource.createQueryRunner();

const user = await this.getById(userId);

const fileId = user.avatar?.id;

if (fileId) {

await queryRunner.connect();

await queryRunner.startTransaction();

try {

await queryRunner.manager.update(User, userId, {

...user,

avatar: null

});

await this.filesService.deletePublicFileWithQueryRunner(fileId, queryRunner);

await queryRunner.commitTransaction();

} catch (error) {

await queryRunner.rollbackTransaction();

throw new InternalServerErrorException();

} finally {

await queryRunner.release();

}

Changes to the configuration

TypeORM made a few significant changes to how we configure our database connection. First, let’s take a look at our current configuration.

database.module.ts

import { Module } from '@nestjs/common';

import { TypeOrmModule } from '@nestjs/typeorm';

import { ConfigModule, ConfigService } from '@nestjs/config';

@Module({

imports: [

TypeOrmModule.forRootAsync({

imports: [ConfigModule],

inject: [ConfigService],

useFactory: (configService: ConfigService) => ({

type: 'postgres',

username: configService.get('POSTGRES_USER'),

password: configService.get('POSTGRES_PASSWORD'),

// ...

entities: [

__dirname + '/../**/*.entity{.ts,.js}',

})

}),

})

export class DatabaseModule {}

Unfortunately, strings with entities, migrations, and subscribers is now deprecated. Therefore, in future TypeORM versions, we will be able only to use entity references.

database.module.ts

import { Module } from '@nestjs/common';

import { TypeOrmModule } from '@nestjs/typeorm';

import { ConfigModule, ConfigService } from '@nestjs/config';

import Post from '../posts/post.entity';

import User from '../users/user.entity';

@Module({

imports: [

TypeOrmModule.forRootAsync({

imports: [ConfigModule],

inject: [ConfigService],

useFactory: (configService: ConfigService) => ({

type: 'postgres',

username: configService.get('POSTGRES_USER'),

password: configService.get('POSTGRES_PASSWORD'),

// ...

entities: [

Post,

User,

// ...

})

}),

})

export class DatabaseModule {}

Having to list all of our entities might be a bit troublesome. Fortunately, @nestjs/typeorm implements the autoLoadEntities option that we can use to auto-load entities.

database.module.ts

import { Module } from '@nestjs/common';

import { TypeOrmModule } from '@nestjs/typeorm';

import { ConfigModule, ConfigService } from '@nestjs/config';

import Address from '../users/address.entity';

@Module({

imports: [

TypeOrmModule.forRootAsync({

imports: [ConfigModule],

inject: [ConfigService],

useFactory: (configService: ConfigService) => ({

type: 'postgres',

username: configService.get('POSTGRES_USER'),

password: configService.get('POSTGRES_PASSWORD'),

entities: [

Address

autoLoadEntities: true,

// ...

})

}),

})

export class DatabaseModule {}

Please notice that we still include the Address entity in the entities array above. The above is because we need to manually add every entity we don’t use through TypeOrmModule.forFeature(). In our case, a good example is the Address entity we use only through a one-to-one relationship.

New array operators

Previously, we had to use raw SQL to run more advanced queries with PostgreSQL arrays.

async getPostsWithParagraph(paragraph: string) {

return this.postsRepository

.query(`SELECT * from post WHERE ${paragraph} = ANY(paragraphs)`);

}

Now, TypeORM 0.3.1 introduced new array operators that can let us handle such cases.

import { ArrayContains } from 'typeorm';

async getPostsWithParagraph(paragraph: string) {

return this.postsRepository

.findBy({

paragraphs: ArrayContains([paragraph])

})

}

Besides the above, we also have the ArrayContainedBy and ArrayOverlap operators.

Other changes

Besides all the changes mentioned so far, TypeORM fixed a ton of minor and significant issues and added performance improvements.

It is worth tracking the changelog in the GitHub releases page.

Some of the important changes are:

requiring NodeJS 14+
supporting TypeScript 4.8
upgrading the ioredis library to v5
supporting the Google Cloud Spanner database,
implementing the FOR KEY SHARE lock mode for PostgreSQL,
possibility of naming primary keys, foreign keys, and indices explicitly,
supporting Common Table Expressions.

Summary

In this article, we’ve gone through the most significant changes made to TypeORM in the last changes. Some of them forced us to refactor our code to be able to bump the TypeORM version we use. All the changes we’ve handled in this article seem like steps in the right direction. A crucial thing to remember is that TypeORM does not follow semantic versioning. Because of that, going from 0.3.0 to 0.3.1 can include breaking changes, for example. Because of that, we need to be super careful when updating TypeORM and read the changelog very carefully to see if it affects our project.

Series Navigation<< API with NestJS #66. Improving PostgreSQL performance with indexes using MikroORMAPI with NestJS #68. Interacting with the application through REPL >>

9 Comments

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Amr

2 years ago

What about custom repositories with Nestjs?

definitely robby krieger

2 years ago

Reply to Amr

What a coincidence. I am having issues with custom repositories too. I am trying this structure. But i got error like below;

Cannot read properties of undefined (reading ‘findOne’)

When i try to console.log it i am getting below;

UserRepository {

target: undefined,

manager: undefined,

queryRunner: undefined

}

You can see the code below:

@Injectable()

export class UserRepository extends Repository<User> {

findOneByBlaBla(blabla: number){

return this.findOne(....);

}

We probably say to nestjs “hey this is a repository initialize it for us” 😀

amehmeto

1 year ago

Reply to Amr

Same issue for me here. I would love to get a solution.

Luga97

2 years ago

Nice post, recently I was suffering with configurations, What about migrations config? I guess this was a breaking change also, how do you manage it?

Kirill

2 years ago

Reply to Luga97

I know only NestJS + Typeorm + Many Crutches = Migrations 🙁 Please show good way.

Author

Marcin Wanago

2 years ago

Reply to Kirill

Hi. I’ve just published a separate article about migrations. I hope it helps you!
http://wanago.io/2022/07/25/api-nestjs-database-migrations-typeorm/

crazyoptimist

2 years ago

Thank you. This is so insightful!

crazyoptimist

2 years ago

An example setup is here.

https://github.com/crazyoptimist/nest-starter

Any feedbacks are welcome!

Ken

2 years ago

Thank you very much. But can you help for another topic relating to this one, after upgrading to version 0.3 typeorm destroyed a lot of old approaches. Can you share how can we can create custom repository for entities for typeorm 0.3