Method select

packages/core/nest-application-context.ts:92–130

* Allows navigating through the modules tree, for example, to pull out a specific instance from the selected module. * @returns {INestApplicationContext}

(
    moduleType: Type<T> | DynamicModule,
    selectOptions?: SelectOptions,
  )

   * @returns {INestApplicationContext}
   */
  public select<T>(
    moduleType: Type<T> | DynamicModule,
    selectOptions?: SelectOptions,
  ): INestApplicationContext {
    const modulesContainer = this.container.getModules();
    const contextModuleCtor = this.contextModule!.metatype;
    const scope = this.scope.concat(contextModuleCtor);

    const moduleTokenFactory = this.container.getModuleTokenFactory();
    const { type, dynamicMetadata } =
      this.moduleCompiler.extractMetadata(moduleType);
    const token = dynamicMetadata
      ? moduleTokenFactory.createForDynamic(
          type,
          dynamicMetadata,
          moduleType as DynamicModule,
        )
      : moduleTokenFactory.createForStatic(type, moduleType as Type);

    const selectedModule = modulesContainer.get(token);
    if (!selectedModule) {
      throw new UnknownModuleException(type.name);
    }

    const options =
      typeof selectOptions?.abortOnError !== 'undefined'
        ? {
            ...this.appOptions,
            ...selectOptions,
          }
        : this.appOptions;

    return new NestApplicationContext(
      this.container,
      options,
      selectedModule,
      scope,
    );
  }

  /**
   * Retrieves an instance of either injectable or controller, otherwise, throws exception.