@aspectjs/persistence

Why ?

Inspired by the Java Persistence API, @aspectjs/persistence is an attempt to bring standardized persistence annotations to javascript. At the moment, different ORM libraries libraries like typeorm or mikro orm bring their own ES decorators to the Object-Relationnal mapping. Altough the decorators are very similar, you cannot switch from one implementation to another without reworking your codebase.

With @aspectjs/persistence, persistence libraries could rely on a standardized API that makes it possible to seamlessly build code on top of it, regardless of the implementation.

At the moment though, the project only offers a @Transactional() annotation, that integrates with typeorm.

Installation

npm i @aspectjs/persistence

danger This project is only intended to work on NodeJS

@Transactional()

• Enable the TransactionalAspect

aop.ts

import { getWeaver } from '@aspectjs/core';
import { TypeOrmTransactionalAspect } from '@aspectjs/persistence/typeorm';
import { DATASOURCE } from './datasource.ts';

getWeaver().enable(new TypeOrmTransactionalAspect().configure(DATASOURCE));

datasource.ts

import { DataSource } from 'typeorm';

export const DATASOURCE = new DataSource({
  type: 'postgres',
  host: 'localhost',
  port: 5432,
  entities: [User, Post],
  synchronize: true,
  ...options,
});

//   DATASOURCE.initialize();

• Declare a transactional method

users.service.ts

import { DATASOURCE } from './datasource.ts';

export class UsersService {
  em = DATASOURCE.manager;
  findAll(): Promise<User[]> {
    return this.usersRepository.find();
  }

  @Transactional()
  async save(user: User) {
    await this.em.save(user);
    for (const post of user.posts) {
      await this.em.save(post);
    }
  }
}

Usage with NestJS

app.module.ts

import { getWeaver } from '@aspectjs/core';
import { TypeOrmTransactionalAspect } from '@aspectjs/persistence/typeorm';
import { Module } from '@nestjs/common';
import { TypeOrmModule } from '@nestjs/typeorm';
import { DataSource } from 'typeorm';
import { Post } from './post.entity';
import { User } from './user.entity';
import { UsersModule } from './users/users.module';
@Module({
  imports: [
    TypeOrmModule.forRootAsync({
      useFactory() {
        return {
          type: 'postgres',
          host: 'localhost',
          port: 5432,
          username: 'user',
          password: 'password',
          database: 'database',
          entities: [
            /* ... */
          ],
        };
      },
      async dataSourceFactory(options) {
        const ds = new DataSource(options!);
        getWeaver().enable(new TypeOrmTransactionalAspect().configure(ds));
        return ds;
      },
    }),
    UsersModule,
  ],
  controllers: [],
  providers: [],
})
export class AppModule {}

users.service.ts

import { Transactional } from '@aspectjs/persistence';
import { Injectable } from '@nestjs/common';
import { InjectRepository } from '@nestjs/typeorm';
import { Repository } from 'typeorm';
import { User } from '../user.entity';

@Injectable()
export class UsersService {
  constructor(
    @InjectRepository(User)
    private usersRepository: Repository<User>,
    @InjectRepository(User)
    private postsRepository: Repository<Post>,
  ) {}

  @Transactional()
  async save(user: User) {
    await this.usersRepository.save(u);
    for (const post of user.posts) {
      await this.postsRepository.save(post);
    }
  }
}