angularangular-cliangular-moduleangular-aotnrwl

Can't load dynamic arguments in an Angular module forRoot import while running with --aot flag


I'm trying to get my code to compile during --aot flag, but it fails where I try to load environment configuration into my logging service that I import in my app.module.ts file. I have code looking like this that runs fine with "ng serve"

This is the structure of what I want to pass over dynamically to my singleton logging service.

// In it's own ts file, not in the module
export interface AppConfiguration {   
  user: User;
  application: ApplicationConfig;
}

// In it's own ts file, not in the module
export const appConfig = (): AppConfiguration => {
  // ... logic happens here to set up the environment, load cookies etc that will result something like this
  const userConf: User = {username: 'ronnrak', name: 'Ronny Raketgevär', id: 1, location: 'a place'};
  const appConf: ApplicationConfig = {defaultLogLevel: 'debug', defaultLogType: 'console'};
  return {user: userConf, application: appConf};
}

logging.module.ts:

export const APP_CONFIG = new InjectionToken<AppConfiguration>('app_config');

@NgModule({
  imports: [CommonModule]
})
export class LoggingModule {
  constructor(@Optional() @SkipSelf() parentModule: LoggingModule) {
    if(parentModule) {
      throw new Error('LoggingModule is already loaded, import in AppModule only.');
    }
  }

  static forRoot(config: AppConfiguration): ModuleWithProviders {
    return {
      ngModule: LoggingModule,
      providers: [
        {provide: APP_CONFIG, useValue: config},
        {provide: LoggingService, useFactory: (conf: AppConfiguration) => {
          return conf.Application.defaultLogType === 'console' ? new ConsoleLoggingService(conf) : new RestLoggingService(conf);
        }, deps:[APP_CONFIG]}
      ]
    };
  }
}

app.module.ts where the error occures

const applicationConfigData: AppConfiguration = appConfig(); <-- error points here

@NgModule({
  declarations: [
    ...
  ],
  imports: [
    ...
    LoggingModule.forRoot(applicationConfigData),
    ...
  ],
  providers: [
    {provide: APP_CONFIG, useValue: applicationConfigData},
    {provide: StoreService, useFactory: (conf: AppConfiguration) => new StoreService(conf), deps: [APP_CONFIG]},
    ...
  ],
  schemas: [
    ...
  ],
  bootstrap: [
    ...
  ]
})
export class AppModule {}

This is the error I get while running --aot

ERROR in apps\project\src\app\app.module.ts(17,49): Error during template compile of 'AppModule'
  Function expressions are not supported in decorators in 'appConfig'
    'appConfig' references 'appConfig'
      'appConfig' contains the error at libs\environment\src\lib\init\app-init.ts(19,26)
        Consider changing the function expression into an exported function.

I've tried to change appConfig without the lambda expression and just a clear exported function, but it didn't work either.

ERROR in apps\project\src\app\app.module.ts(17,49): Error during template compile of 'AppModule'
  Function calls are not supported in decorators but 'appConfig' was called.

How do I load dynamic data into my singleton service from app.module?


Solution

  • You should export the useFactory function of the LoggingService and the StoreService, because, and I quote trichetriche

    You simply can't use function calls in decorators

    LoggingService

    export function loggingFactory(conf: AppConfiguration) {
      return conf.Application.defaultLogType === 'console' ? 
        new ConsoleLoggingService(conf) : new RestLoggingService(conf);
    }
    
    {
      provide: LoggingService, 
      useFactory: loggingFactory, 
      deps:[APP_CONFIG]
    }
    

    And the StoreService:

    export function storeFactory(conf: AppConfiguration) {
      return new StoreService(conf);
    }
    
    {
      provide: StoreService, 
      useFactory: storeFactory, 
      deps: [APP_CONFIG]
    },
    

    But this one seems a bit obsolete, because you can just use the service directly and inject the APP_CONFIG using @Inject()

    @Injectable()
    export class StoreService {
      constructor(@Inject(APP_CONFIG) appConfig: AppConfiguration) {}
    }