Typeorm Transactional

Overview

typeorm-transactional is a fork of typeorm-transactional-cls-hooked designed for newer versions of TypeORM. It provides a @Transactional decorator and utilities to manage transactions seamlessly using AsyncLocalStorage (ALS) or cls-hooked.

Key Features

• Simplifies transaction management in TypeORM.
• Supports multiple DataSource instances.
• Provides hooks for transaction lifecycle events.
• Compatible with modern TypeORM APIs (DataSource instead of Connection).

Table of Contents

• Installation
• Initialization
• Usage
  • Transactional Decorator
  • Data Sources
  • Transaction Propagation
  • Isolation Levels
• Hooks
• Unit Test Mocking
• API Reference
• Custom Extensions

Installation

Install the library and its required dependencies:

# Using npm
npm install --save typeorm-transactional-extension typeorm reflect-metadata

# Using yarn
yarn add typeorm-transactional-extension typeorm reflect-metadata

Note: Ensure reflect-metadata is imported globally in your application. See TypeORM Installation Guide.

Initialization

Before using the library, initialize the transactional context before your application starts:

import { initializeTransactionalContext, StorageDriver } from 'typeorm-transactional-extension';

initializeTransactionalContext({ storageDriver: StorageDriver.AUTO });

For example, in an Express app:

import express from 'express';
import { initializeTransactionalContext, StorageDriver } from 'typeorm-transactional-extension';

initializeTransactionalContext({ storageDriver: StorageDriver.AUTO });

const app = express();
// Your app setup here

Important: Call initializeTransactionalContext before initializing your application context.

Usage

Transactional Decorator

Use the @Transactional() decorator to make service methods transactional:

import { Transactional } from 'typeorm-transactional-extension';

export class PostService {
  constructor(private readonly repository: PostRepository) {}

  @Transactional()
  async createPost(id: number, message: string): Promise<Post> {
    const post = this.repository.create({ id, message });
    return this.repository.save(post);
  }
}

Advanced Example

You can also use DataSource or EntityManager objects within transactions:

export class PostService {
  constructor(
    private readonly repository: PostRepository,
    private readonly dataSource: DataSource
  ) {}

  @Transactional()
  async createAndFetchPost(id: number, message: string): Promise<Post> {
    const post = this.repository.create({ id, message });
    await this.repository.save(post);

    return this.dataSource
      .createQueryBuilder(Post, 'p')
      .where('id = :id', { id })
      .getOne();
  }
}

Data Sources

To use transactions with TypeORM entities, register your DataSource using addTransactionalDataSource:

import { DataSource } from 'typeorm';
import { addTransactionalDataSource } from 'typeorm-transactional-extension';

const dataSource = new DataSource({
  type: 'postgres',
  host: 'localhost',
  port: 5432,
  username: 'postgres',
  password: 'postgres',
});

addTransactionalDataSource(dataSource);

For multiple DataSource instances, specify a custom name:

addTransactionalDataSource({
  name: 'secondary',
  dataSource: new DataSource({ /* config */ }),
});

Transaction Propagation

Propagation defines how transactions interact with existing ones. Supported options:

• MANDATORY: Requires an existing transaction; throws an error if none exists.
• NESTED: Creates a nested transaction if one exists; otherwise behaves like REQUIRED.
• NEVER: Executes non-transactionally; throws an error if a transaction exists.
• NOT_SUPPORTED: Executes non-transactionally; suspends the current transaction if one exists.
• REQUIRED (default): Uses the current transaction or creates a new one if none exists.
• REQUIRES_NEW: Always creates a new transaction, suspending any existing one.
• SUPPORTS: Uses the current transaction if one exists; otherwise executes non-transactionally.

Isolation Levels

Isolation levels control how transactions interact with each other. Supported levels:

• READ_UNCOMMITTED: Allows dirty reads, non-repeatable reads, and phantom reads.
• READ_COMMITTED: Prevents dirty reads; allows non-repeatable reads and phantom reads.
• REPEATABLE_READ: Prevents dirty and non-repeatable reads; allows phantom reads.
• SERIALIZABLE: Prevents dirty reads, non-repeatable reads, and phantom reads.

Hooks

Use hooks to execute logic during transaction lifecycle events:

• runOnTransactionCommit(cb): Executes after a transaction commits.
• runOnTransactionRollback(cb): Executes after a transaction rolls back.
• runOnTransactionComplete(cb): Executes after a transaction completes (success or failure).

Example:

import { runOnTransactionCommit } from 'typeorm-transactional-extension';

@Transactional()
async createPost(id: number, message: string): Promise<Post> {
  const post = this.repository.create({ id, message });
  const result = await this.repository.save(post);

  runOnTransactionCommit(() => {
    console.log('Transaction committed!');
  });

  return result;
}

Unit Test Mocking

To mock @Transactional in unit tests (e.g., with Jest):

jest.mock('typeorm-transactional-extension', () => ({
  Transactional: () => () => ({}),
}));

API Reference

initializeTransactionalContext(options): void

Initializes the transactional context. Options:

{
  storageDriver?: StorageDriver;
  maxHookHandlers?: number;
}

• storageDriver: Mechanism for transaction propagation (AUTO, CLS_HOOKED, or ASYNC_LOCAL_STORAGE).
• maxHookHandlers: Maximum number of hooks allowed (default: 10).

addTransactionalDataSource(input): DataSource

Registers a DataSource for transactional use. Example:

addTransactionalDataSource(new DataSource({ /* config */ }));

runInTransaction(fn, options?): Promise<any>

Executes a function within a transactional context. Example:

await runInTransaction(async () => {
  // Your transactional logic here
}, { propagation: 'REQUIRES_NEW' });

wrapInTransaction(fn, options?): WrappedFunction

Wraps a function in a transactional context. Example:

const wrappedFn = wrapInTransaction(async () => {
  // Your logic here
});
await wrappedFn();

runOnTransactionCommit(cb): void

Registers a callback to execute after a transaction commits.

runOnTransactionRollback(cb): void

Registers a callback to execute after a transaction rolls back.

runOnTransactionComplete(cb): void

Registers a callback to execute after a transaction completes.

Custom Extensions

This library also provides custom extensions for TypeORM's Repository to simplify common database operations. These extensions include:

Extended Repository Methods

1. insertOrFail
   Inserts an entity and throws an error if no identifiers are returned.

2. updateOrFail
   Updates an entity and throws an error if no rows are affected.

3. deleteOrFail
   Deletes an entity and throws an error if no rows are affected.

Usage

To use these extensions, simply import and use the Repository methods as usual. The extensions are automatically applied.

Example

import { Repository } from 'typeorm';
import { MyEntity } from './entities/my-entity';

export class MyService {
  constructor(private readonly repository: Repository<MyEntity>) {}

  async createEntity(data: Partial<MyEntity>): Promise<number> {
    return this.repository.insertOrFail(data);
  }

  async updateEntity(id: number, data: Partial<MyEntity>): Promise<void> {
    await this.repository.updateOrFail({ id }, data);
  }

  async deleteEntity(id: number): Promise<void> {
    await this.repository.deleteOrFail({ id });
  }
}

Method Details

insertOrFail

Inserts an entity and ensures that the operation returns identifiers. If no identifiers are returned, an error is thrown.

repository.insertOrFail(entity, 'Custom error message if insert fails');

updateOrFail

Updates an entity based on the given criteria. If no rows are affected, an error is thrown.

repository.updateOrFail(criteria, partialEntity, 'Custom error message if update fails');

deleteOrFail

Deletes an entity based on the given criteria. If no rows are affected, an error is thrown.

repository.deleteOrFail(criteria, 'Custom error message if delete fails');

For more details, refer to the API Documentation.