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,
})

WARNING

An EntityManager passed this way must already be available before the app bootstraps. The module does not initialize MikroORM on its behalf.

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',
  }),
})