how the parameters of a forRoot() module's method is passed to a provider?

Question

I found some examples of module\'s forRoot() method like the one below:

export class CoreModule {
constructor(
@Optional()
@SkipSelf()
parentModule: CoreModu         


        

Answer 1

Use InjectionToken to register the parameters with the injector. Then use DI passing in the InjectionToken with the deps property as follows:

export const Params= new InjectionToken('params');

...

static forRoot(someParameters?:string[]): ModuleWithProviders {
  return {
  ngModule: CoreModule,
  providers: [
            { provide: Params, useValue: someParameters },
            { provide: AnProvider1, useClass: AnProvider1, deps:[Params] },
            AnProvider2
  ]
};

In your component constructor, use the InjectionToken:

constructor(@Inject(Params) someParameters: string[])