@ttoss/postgresdb

A lightweight Sequelize wrapper for PostgreSQL databases with TypeScript support.

Installation

pnpm add @ttoss/postgresdb
pnpm add -D @ttoss/postgresdb-cli

ESM only: Add "type": "module" to your package.json.

Quick Start

Database Setup

Use Docker to create a PostgreSQL instance:

docker run --name postgres-test -e POSTGRES_PASSWORD=mysecretpassword -d -p 5432:5432 postgres

Or with Docker Compose (docker-compose.yml):

services:
  db:
    image: postgres
    environment:
      POSTGRES_PASSWORD: mysecretpassword
    volumes:
      - db-data:/var/lib/postgresql/data
    ports:
      - '5432:5432'

volumes:
  db-data:

docker compose up -d

Define Models

Create models/User.ts:

import { Table, Column, Model } from '@ttoss/postgresdb';

@Table
export class User extends Model<User> {
  @Column
  declare name: string;

  @Column
  declare email: string;
}

Important: You must use the declare keyword on class properties to ensure TypeScript doesn't emit them as actual fields. Without declare, public class fields would shadow Sequelize's getters and setters, blocking access to the model's data. See Sequelize documentation on public class fields for details.

All sequelize-typescript decorators are available.

Export in models/index.ts:

export { User } from './User';

Initialize Database

Create src/db.ts:

import { initialize } from '@ttoss/postgresdb';
import * as models from './models';

export const db = await initialize({ models });

Configuration

Option 1 - Direct configuration:

export const db = initialize({
  database: 'mydb',
  username: 'user',
  password: 'pass',
  host: 'localhost',
  port: 5432,
  models,
});

Option 2 - Environment variables (.env):

DB_NAME=postgres
DB_USERNAME=postgres
DB_PASSWORD=mysecretpassword
DB_HOST=localhost
DB_PORT=5432

Environment variables are automatically used if defined.

Sync Schema

Synchronize database schema with models:

pnpm dlx @ttoss/postgresdb-cli sync

This imports db from src/db.ts and syncs the schema.

CRUD Operations

All models are accessible via the db object. See Sequelize documentation for complete query API.

import { db } from './db';

const user = await db.User.create({
  name: 'John Doe',
  email: '[email protected]',
});

Monorepo Usage

Share models across packages with this setup:

In the database package (@yourproject/postgresdb):

package.json:

{
  "type": "module",
  "exports": "./src/index.ts"
}

src/index.ts:

export * as models from './models';

Don't export db here - each package may need different configurations.

In consuming packages:

Add dependencies to package.json:

{
  "dependencies": {
    "@ttoss/postgresdb": "^x.x.x",
    "@yourproject/postgresdb": "workspace:^"
  }
}

Update tsconfig.json:

{
  "compilerOptions": {
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true
  },
  "include": ["src", "../postgresdb/src"]
}

Create src/db.ts:

import { initialize } from '@ttoss/postgresdb';
import { models } from '@yourproject/postgresdb';

export const db = initialize({ models });

Testing

Testing models with decorators requires special configuration because Jest's Babel transformer doesn't properly transpile TypeScript decorators. The solution is to build your models before running tests.

Why test your models? Beyond validating functionality, tests serve as a critical safety check for schema changes. They ensure that running sync --alter won't accidentally remove columns or relationships from your database. If a model property is missing or incorrectly defined, tests will fail before you can damage production data.

Setup

1. Install dependencies:

pnpm add -D @testcontainers/postgresql jest @types/jest

2. Configure tsconfig.json:

{
  "compilerOptions": {
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true
  }
}

These options are required for decorator support. Without them, TypeScript won't properly compile decorator metadata.

3. Add build script to package.json:

{
  "scripts": {
    "build": "tsup",
    "pretest": "pnpm run build",
    "test": "jest"
  }
}

The pretest script ensures models are built before tests run.

Test Example

import {
  PostgreSqlContainer,
  StartedPostgreSqlContainer,
} from '@testcontainers/postgresql';
import { initialize, Sequelize } from '@ttoss/postgresdb';
import { models } from 'dist/index'; // Import from built output

let sequelize: Sequelize;
let postgresContainer: StartedPostgreSqlContainer;

jest.setTimeout(60000);

beforeAll(async () => {
  // Start PostgreSQL container
  postgresContainer = await new PostgreSqlContainer('postgres:17').start();

  // Initialize database with container credentials
  const db = await initialize({
    models,
    logging: false,
    username: postgresContainer.getUsername(),
    password: postgresContainer.getPassword(),
    database: postgresContainer.getDatabase(),
    host: postgresContainer.getHost(),
    port: postgresContainer.getPort(),
  });

  sequelize = db.sequelize;

  // Sync database schema
  await sequelize.sync();
});

afterAll(async () => {
  await sequelize.close();
  await postgresContainer.stop();
});

describe('User model', () => {
  test('should create and retrieve user', async () => {
    const userData = { email: '[email protected]' };
    const user = await models.User.create(userData);

    const foundUser = await models.User.findByPk(user.id);
    expect(foundUser).toMatchObject(userData);
  });
});

Key Points

• Import from dist/: Tests must import models from the compiled output (dist/index), not source files, because decorators aren't transpiled by Jest's Babel transformer. See this Stack Overflow answer for details.
• Testcontainers: Use @testcontainers/postgresql to spin up isolated PostgreSQL instances for each test run.
• Timeout: Set a longer timeout with jest.setTimeout(60000) as container startup can take time.
• Sync schema: Call sequelize.sync() after initialization to create tables based on your models.
• Schema validation: Tests verify that all model properties are correctly defined. This prevents sync --alter from accidentally removing database columns due to missing or misconfigured model properties.

For a complete working example with full test configuration, see the terezinha-farm/postgresdb example in this repository.

API Reference

initialize(options)

Initializes database connection and loads models.

Options: All Sequelize options except dialect (always postgres), plus:

• models (required): Object mapping model names to model classes

Decorators

All sequelize-typescript decorators are exported: @Table, @Column, @ForeignKey, etc.

Types

ModelColumns<T>

Extracts column types from a model:

import { Column, Model, type ModelColumns, Table } from '@ttoss/postgresdb';

@Table
class User extends Model<User> {
  @Column
  declare name?: string;

  @Column
  declare email: string;
}

// Inferred type: { name?: string; email: string; }
type UserColumns = ModelColumns<User>;