Multiple loaders yet only one schema class

[smolinari]

Hi,

I'm about to try it out, but I figured I'd ask first.

If I use multiple loaders, and say I have nested objects for two sets of config data, one set is environment variables (from the one loader) and one from a database (from another loader), will nest-typed-config know to "fill in" the right object properties automatically?

I'd imagine so, but the docs aren't clear about it.

Scott

[Nikaple]

Your config is recursively merged, check out the source code.

[smolinari]

Thanks. @Nikaple. Appreciate the help. One last open challenge I have is creating a loader that would use a database service to get config information. Is this even possible? I'm not seeing how to get a service injected as the loader.

Scott

[Nikaple]

That's not possible. As the most fundamental module of your application, config module should not rely on any other modules, and that's why we didn't even provide an option to inject other services. But, however, you can define your own "config-from-database" providers with Nest's custom providers functionality. Such as:

import { DatabaseModule, DatabaseService } from './database.module';

export class ConfigFromDatabaseSchema {
  someConfig: string;
}

@Module({
  imports: [DatabaseModule],
  providers: [
    {
      provide: ConfigFromDatabaseSchema,
      useFactory(databaseService) {
        // validation is omitted for simplicity
        return databaseService.query('select * from config limit 1')
      },
      inject: [DatabaseService]
    }
  ],
})
export class DatabaseConfigModule {}

Then you can inject your "config-from-database" with ConfigFromDatabaseSchema, please refer to Nest's documentation for more information.

[smolinari]

Hey. Thanks so much @Nikaple. I understand the config being fundamental part and the direction you suggest is where I was heading too.

Appreciate the support. Keep up the good work!

Scott

[smolinari]

@Nikaple - Just wanted to let you know, like your suggestion above, I put together a factory provider to generate the config from the database. Works like a charm. Thanks for your help and your package (which I'm still using for the env config).

Scott

[Nikaple]

Glad that it works, you're welcome 😸