I'm experiencing strange behavior of services injected to a component that is loaded dynamically. Consider the following service
@Injectable({
providedIn: 'root'
})
export class SomeService {
private random = Math.random() * 100;
constructor() {
console.log('random', this.random);
}
}
The service is added as a dependency to two components. First component is a part of lazy-loaded module. While second one is loaded dynamically. The following service loads modules with dynamic component
export const COMPONENT_LIST = new InjectionToken<any>('COMPONENT_LIST');
export const COMPONENT_TYPE = new InjectionToken<any>('COMPONENT_TYPE');
@Injectable({
providedIn: 'root'
})
export class LoaderService {
constructor(
private injector: Injector,
private compiler: Compiler,
) { }
getFactory<T>(componentId: string): Observable<ComponentFactory<T>> {
// COMPONENT_LIST is passed through forRoot() from the module that declares first component
const componentList = this.injector.get(COMPONENT_LIST);
const m = componentList.find(m => m.componentId === componentId);
const promise: Promise<ComponentFactory<T>> = (!m) ? null :
m.loadChildren
.then((mod: any) => {
return this.compiler.compileModuleAsync(mod);
})
.then((mf: NgModuleFactory<any>) => {
const mr: NgModuleRef<any> = mf.create(this.injector);
const type: Type<T> = mr.injector.get<Type<T>>(COMPONENT_TYPE); // DYNAMIC_COMPONENT is provided in loaded module
return mr.componentFactoryResolver.resolveComponentFactory<T>(dynamicComponentType);
});
return from(promise);
}
}
In the same module I declare the following component (to place component that is loaded dynamically) and directive
@Component({
selector: 'dynamic-wrapper',
template: `<ng-container dynamicItem></ng-container>`
})
export class DynamicWrapperComponent implements AfterViewInit, OnDestroy {
@Input() itemId: string;
@Input() inputParameters: any;
@ViewChild(DynamicItemDirective)
private dynamicItem: DynamicItemDirective;
private unsubscribe$: Subject<void> = new Subject();
constructor(
private loaderService: LoaderService
) { }
ngAfterViewInit(): void {
this.loaderService.getComponentFactory(this.itemId).subscribe((cf: ComponentFactory<any>) => {
this.dynamicItem.addComponent(cf, this.inputParameters);
});
}
}
...
@Directive({
selector: '[dynamicItem]'
})
export class DynamicItemDirective {
constructor(protected viewContainerRef: ViewContainerRef) { }
public addComponent(cf: ComponentFactory<any>, inputs: any): void {
this.viewContainerRef.clear();
const componentRef: ComponentRef<any> = this.viewContainerRef.createComponent(cf);
Object.assign(componentRef.instance, inputs);
// if I do not call detectChanges, ngOnInit in loaded component will not fire up
componentRef.changeDetectorRef.detectChanges();
}
}
SomeService
is defined in a separate module that is imported in both lazy-loaded module with first component and dynamically loaded module.
After both components are initialed I see output of console.log('random', this.random)
with two different numbers in console, despite providedIn: 'root'
in decorator. What is the reason for such a strange behavior?
from Angular: understanding how DI works in dynamicaly loaded component
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