FeatureModule does not work during AOT build when static forRoot has arguments

Question

I ran into an AOT build problem using Angular @ 5.1.0.

Mistake:

ERROR in Error during template compile of 'AppModule'
  Function calls are not supported in decorators but 'FeatureModule' was called.

feature.module.ts

@NgModule({
    imports: [
        BrowserModule,
        RouterModule.forRoot([])
    ],
    declarations: [
        ...    
    ],
    exports: [
        ...      
    ]
})
export class FeatureModule{
    static forRoot(items:any[]): ModuleWithProviders {
        const routes:Routes = items.map(t=> {
            return { path: t.name, component: t.component };
        });

        return {
            ngModule: FeatureModule, 
            providers: [
                provideRoutes(routes)
            ]
        }
    }
}

This compiles successfully in non-aot builds. This only seems to be a problem for building AOT.

Why is this error occurring?

Answer 1

Well, it took me a while to figure this out. TL; DR: the method forRootshould be simple, otherwise the AOT compiler complains.

To make this simple, I had to:

• Remove branching logic and function calls from a method forRoot.

• factory, forRoot.

• Router.resetConfig factory.

• ANALYZE_FOR_ENTRY_COMPONENTS, entryComponents .

• RouterModule.forChild([]) FeatureModule, @angular/router.

• RouterModule.forRoot([]) AppModule, Router.

export const Items = new InjectionToken<any[]>('items');
export function InitMyService(router:Router, items:any[]) {
     var routes:Routes =  items.map(t=> { return { path: t.name, component: t.component, outlet: 'modal' }});
     var r = router.config.concat(routes);
     router.resetConfig(r);        
     return new MyService(router);
}


@NgModule({
    imports: [
        CommonModule,
        RouterModule.forChild([])
    ],
    declarations: [
        MyComponent
    ],
    exports: [
        MyComponent
    ],
    providers: [

    ]
})
export class FeatureModule {
    static forRoot(items:any[]): ModuleWithProviders {
        return {
            ngModule: FeatureModule, 
            providers: [
                { provide: Items, useValue: items},
                { provide: ANALYZE_FOR_ENTRY_COMPONENTS, multi: true, useValue: items},
                { provide: MyService, useFactory: InitMyService, deps:[Router, Items] }
            ]
        }
    }
}

app.module.ts

@NgModule({
  imports:      [ 
      BrowserModule,
      RouterModule.forRoot([]),
      FeatureModule.forRoot([{name: 'test', component: TestComponent}])
    ],
  declarations: [ AppComponent, TestComponent ],
  bootstrap:    [ AppComponent ],
  providers: [
  ],
  exports: [AppComponent]
})
export class AppModule {
}

, RouterModule.forChild() - . , RouterModule - . AppModule Router , RouterModule.forRoot() AppModule.