typeorm-seeding

import { createConnection, Connection, Entity, PrimaryGeneratedColumn, Column } from 'typeorm'; import { define, runSeeder, Factory, Seeder } from 'typeorm-seeding'; import * as Faker from 'faker'; // Using faker-js/faker in modern context // 1. Define Entity @Entity() export class User { @PrimaryGeneratedColumn('uuid') id: string = ''; @Column({ nullable: true }) name: string = ''; @Column() email: string = ''; } // 2. Define Factory for the User entity define(User, (faker: typeof Faker) => { const user = new User(); user.name = faker.name.findName(); user.email = faker.internet.email(); return user; }); // 3. Define a Seeder class class UserCreateSeeder implements Seeder { public async run(factory: Factory, connection: Connection): Promise<any> { console.log('Running UserCreateSeeder...'); await factory(User)().createMany(5); // Create 5 users using the factory console.log('Created 5 users.'); } } // 4. Programmatic execution of the seeder async function seedDatabase() { let connection: Connection | undefined; try { // Establish a TypeORM connection (using in-memory SQLite for quick demo) connection = await createConnection({ type: 'sqlite', database: ':memory:', entities: [User], synchronize: true, // Auto-create schema for demo purposes logging: false, }); await connection.synchronize(true); // Ensure schema is created console.log('Database connection established. Starting seeding...'); await runSeeder(UserCreateSeeder); // Execute the defined seeder console.log('Seeding complete.'); // Verify seeded data const userRepository = connection.getRepository(User); const users = await userRepository.find(); console.log('Users in DB:', users.map(u => u.name)); } catch (error) { console.error('Seeding failed:', error); } finally { if (connection && connection.isConnected) { await connection.close(); console.log('Database connection closed.'); } } } seedDatabase();