Getting started

NestJS module for mikroorm-seeder. Runs your @Seeder classes automatically on application bootstrap — once per seeder by default, tracked in a database table so watch-mode restarts do not re-seed. For simple cases, a run callback lets you seed without any class boilerplate.

INFO

This package handles the NestJS integration. The seeding itself — @Seed(), @Seeder, seed(), entity factories — is all defined in mikroorm-seeder. Familiarity with that package will make this one much easier to use.

Installation

npm

npm install @joakimbugge/nest-mikroorm-seeder @joakimbugge/mikroorm-seeder

yarn

yarn add @joakimbugge/nest-mikroorm-seeder @joakimbugge/mikroorm-seeder

pnpm

pnpm add @joakimbugge/nest-mikroorm-seeder @joakimbugge/mikroorm-seeder

The peer dependencies (@nestjs/common, @nestjs/core, @mikro-orm/core, @mikro-orm/nestjs, reflect-metadata) are required, but if you are adding this to an existing NestJS + MikroORM project they are already present.

Basic usage

Import SeederModule in your root module. It auto-detects the MikroORM instance registered by MikroOrmModule, so no extra wiring is needed in the common case:

import { Module } from '@nestjs/common'
import { MikroOrmModule } from '@mikro-orm/nestjs'
import { SeederModule } from '@joakimbugge/nest-mikroorm-seeder'
import { UserSeeder } from './seeders/UserSeeder.js'

@Module({
  imports: [
    MikroOrmModule.forRoot({ ... }),
    SeederModule.forRoot({ seeders: [UserSeeder] }),
  ],
})
export class AppModule {}

If your seeders declare dependencies on each other via the @Seeder decorator, they are sorted and executed in the correct order automatically — see seeder suites for details.

seeders also accepts glob patterns alongside constructors. Patterns are expanded at bootstrap time and only classes decorated with @Seeder are collected:

SeederModule.forRoot({ seeders: [UserSeeder, 'dist/seeders/**/*.js'] })

TypeScript source files work too — no extra configuration needed. When running via nest start or ts-node, the TypeScript loader is already active and .ts patterns resolve just like .js ones:

SeederModule.forRoot({ seeders: ['src/seeders/**/*.ts'] })

Providing an EntityManager explicitly

If you manage MikroORM yourself rather than through MikroOrmModule, pass an EntityManager directly:

SeederModule.forRoot({
  seeders: [UserSeeder],
  em: myEntityManager,
})

Async configuration

Use forRootAsync to resolve options from the DI container — useful when the EntityManager or environment config is injected:

import { ConfigService } from '@nestjs/config'

SeederModule.forRootAsync({
  imports: [ConfigModule],
  inject: [ConfigService],
  useFactory: (config: ConfigService) => ({
    seeders: [UserSeeder],
    enabled: config.get('SEED') === 'true',
  }),
})