Using TypeORM with env in NestJS

The way I initially used TypeORM was to use TypeOrmModule in an AppModule.

And You can be found in the official documentation.

Documentation | NestJS - A progressive Node.js framework

import { Module } from '@nestjs/common';
import { TypeOrmModule } from '@nestjs/typeorm';

@Module({
  imports: [
    TypeOrmModule.forRoot({
      type: 'mysql',
      host: 'localhost',
      port: 3306,
      username: 'root',
      password: 'root',
      database: 'test',
      entities: [],
      synchronize: true,
    }),
  ],
})
export class AppModule {}

I’m trying to separate TypeORM configuration into different files and use .env.

First, I created database.config.js in config folder.
And I used Configservice to use .env.

import { Injectable } from '@nestjs/common';
import { TypeOrmModuleOptions, TypeOrmOptionsFactory } from '@nestjs/typeorm';
import { ConfigService } from '@nestjs/config';

@Injectable()
export class TypeOrmConfigService implements TypeOrmOptionsFactory {
  constructor(private configService: ConfigService) {}

  createTypeOrmOptions(): TypeOrmModuleOptions {
    return {
      type: 'mysql',
      host: this.configService.get<string>('DB_HOST'),
      port: +this.configService.get<number>('DB_PORT'),
      username: this.configService.get<string>('DB_NAME'),
      password: this.configService.get<string>('DB_PASSWORD'),
      database: this.configService.get<string>('DB_DATABASE'),
      entities: ['dist/**/**/*.entity.{ts,js}'],
      synchronize: false,
    };
  }
}

The AppModule was also modified.

@Module({
  imports: [
    ConfigModule.forRoot(),
    TypeOrmModule.forRootAsync({
      imports: [ConfigModule],
      useClass: TypeOrmConfigService,
    }),
  ],
  providers: [AppService],
  controllers: [AppController],
})
export class AppModule {
  constructor(private dataSource: DataSource) {}
}

That’s it.

There are many ways, and my solution is different.

You can use process.env instead of ConfigService.
And I didn’t use the global option.

Even in the AppModule I didn’t use useExisting but useClass.

I hope you solve it in your own way.