Description

Dependency injection and service container integration with TypeOrm using InversifyJs library.

The implementation is strongly inspired by @nestjs/typeorm.

Usage

We assume that you are familiar with TypeOrm.

Install the required dependencies.

npm install --save inversify-typeorm

We need at least one entity, so we define the User entity firstly.

// user.entity.ts

import { Entity, PrimaryGeneratedColumn, Column } from 'typeorm'

@Entity()
export class User {
  @PrimaryGeneratedColumn()
  id!: number

  @Column()
  name!: string
}

To use Datasource and EntityManager, we need to bind them to the container using TypeOrmManager.importRoot(), and they will be available to inject across the entire project.

• Note: To begin using the User entity, we need to let TypeORM know about it by inserting it into the entities array (unless you use a static glob path).

// app.ts

import { TypeOrmManager } from 'inversify-typeorm'
import { User } from './user.entity'

await TypeOrmManager.importRoot({
  type: 'mysql',
  host: 'localhost',
  port: 5432,
  username: 'test',
  password: 'test',
  database: 'test',
  synchronize: true,
  logging: false,
  entities: [User],
  migrations: [],
  subscribers: [],
})

TypeORM supports the repository design pattern, so each entity has its own repository. These repositories can be obtained from the database data source.

We can use TypeOrmManager.importRepository() to define which repositories are bound to the container. So the bound repositories will be also available to inject across the entire project.

// app.ts

await TypeOrmManager.importRepository([User])

Let's define the UserService to operate User entities.

Then we can inject the DataSource, EntityManager or UsersRepository into the UsersService:

• inject DataSource using the @InjectDataSource()
• inject EntityManager using the @InjectEntityManager()
• inject UsersRepository using the @InjectRepository()

And the UserService also needed to be bounded to the container by @Service(), so that it can be created correctly by the container using the injected DataSource, EntityManager or UsersRepository.

// user.service.ts

import { DataSource, EntityManager, Repository } from 'typeorm'
import { InjectDataSource, InjectRepository, InjectEntityManager, Service } from 'inversify-typeorm'
import { User } from './user.entity'

@Service()
export class UserService {
  @InjectDataSource()
  private dataSource!: DataSource

  @InjectEntityManager()
  private entityManager!: EntityManager

  constructor(@InjectRepository(User) private repository: Repository<User>) {}

  saveByRepository(user: User): Promise<User> {
    return this.repository.save(user)
  }

  saveByManager(user: User): Promise<User> {
    return this.entityManager.save(user)
  }

  async saveManyByTransaction(users: User[]): Promise<void> {
    const queryRunner = this.dataSource.createQueryRunner()

    await queryRunner.connect()
    await queryRunner.startTransaction()
    try {
      for (const user of users) {
        await queryRunner.manager.save(user)
      }
      await queryRunner.commitTransaction()
    } catch (err) {
      await queryRunner.rollbackTransaction()
    } finally {
      await queryRunner.release()
    }
  }

  findAll(): Promise<User[]> {
    return this.repository.find()
  }
}

It's time to get the created UserService from the container by container.get<UserService>(UserService.name) and operate User entities!

// app.ts

import { contanier } from 'inversify-typeorm'

const userOne = new User()
userOne.id = 1
userOne.name = `Alice`

const userTwo = new User()
userTwo.id = 2
userTwo.name = `Bob`

const userThree = new User()
userThree.id = 3
userThree.name = `Olivia`

const userFour = new User()
userFour.id = 4
userFour.name = `Ada`

const service = container.get<UserService>(UserService.name)

/** Save through the various methods. */
await service.saveByRepository(userOne)
await service.saveByManager(userTwo)
await service.saveManyByTransaction([userThree, userFour])

/** Load the saved users so we can assert on them. */
const userList = await service.findAll()
console.log({ userList })

At last, we can close the connection with the database. Once connection is closed, we cannot use repositories or perform any operations except opening connection again.

// app.ts

try {
  await TypeOrmManager.destroyDataSource()
} cache (e) {
  // log error
}

Examples

All examples are available here.