nestjs-seeder streamlines the process of populating your NestJS application with mock data. It makes it easy to generate and manage seed data, ideal for testing and simulating API responses.

Installation 🤖

Install the nestjs-seeder package with:

npm install @hodfords/nestjs-seeder --save

Usage 🚀

To seed fake user data into your database, follow these 6 steps:

1. Define the Factory

First, create a factory for UserEntity. This factory will generate fake data for user records.

user.factory.ts

import { define } from '@hodfords/nestjs-seeder';

interface SeedUserOptions {
    countryId: string;
}

class UserEntity {
    name: string;
    age: string;
    countryId: string;
    createdAt: Date;
}

define(UserEntity, (options: SeedUserOptions) => {
    const user = new UserEntity();

    user.name = faker.name.title();
    user.age = faker.datatype.number(100);
    user.createdAt = faker.date.future();

    return plainToClassFromExist(user, options || {});
});

2. Create the BaseSeeder

Create a base seeder class that will be used to configure and run your seeding logic.

base.seeder.ts

import { Test } from '@nestjs/testing';
import { AppModule } from '~app.module';
import { databaseConfig } from '~config/database.config';
import { BaseSeeder as AbstractSeeder } from '@hodfords/nestjs-seeder';

export abstract class BaseSeeder extends AbstractSeeder {
    createModule() {
        return Test.createTestingModule({
            imports: [AppModule, databaseConfig]
        }).compile();
    }

    abstract run(): Promise<void>;
}

3. Create the UserSeed

Implement a seeder class that extends BaseSeeder. Use the factory methods to generate and save data.

There are 3 methods to seed a fake data from factory method

createOne(options?: any): Entity;
saveOne(options?: any): Promise<Entity>;
saveMany(count: number, options?: any): Promise<Entity[]>;

user.seed.ts

import { BaseSeeder } from '~core/seeders/base-seeder';
import { factory } from '@hodfords/nestjs-seeder';
import faker from 'faker';

export class UserSeed extends BaseSeeder {
    async run() {
        const countryId = (await factory(CountryEntity)).id;

        await factory(UserEntity).saveOne({ countryId }); // 1
        factory(UserEntity).createOne({ countryId }); // 2
        await factory(UserEntity).saveMany(100, { countryId }); // 3
    }
}

4. Create the seedConfig

Set up the seed configuration to include your seed classes.

import { SeederModule } from '@hodfords/nestjs-seeder';
export const seedConfig = SeederModule.forRoot([UserSeed]);

5. Import seedConfig into AppModule

Integrate the seed configuration into your main application module.

@Module({
    imports: [seedConfig],
    controllers: [AppController],
    providers: []
})
export class AppModule {}

6. Run the seeder

Execute the seeder command to populate your database with the defined fake data.

wz-command seeder

License 📝

This project is licensed under the MIT License