Angular - How to share a service provided in component with the component's resolver?-CodePudding

I have a messenger component, with a messages service provided in the component itself (as it needs to be component specific) as such:

@Component({
  selector: "app-messenger",
  templateUrl: "./messenger.page.html",
  styleUrls: ["./messenger.page.scss"],
  providers: [MessagesService],
})

I need to load my messages (done in the messages service) before I transition to the messenger component, and am therefore using a resolver (messagesResolver). The messagesService contains the messages, so the resolver needs access to a same instance of the messagesService as the messengerComponent.

How do I do that?

I am currently getting the error from the resolver:

NullInjectorError: R3InjectorError(MainPageModule)[MessagesResolver -> MessagesResolver -> MessagesService -> MessagesService -> MessagesService]: 
  NullInjectorError: No provider for MessagesService!

I understood from other Stack Overflow questions that I could Angular's Injector? However I don't know how I would go about this.

Notes on resolver:

It is provided in root using @Injectable({ providedIn: "root", })
It is used in the routing of the module containing the messenger component as such:

{
    path: "messenger/:chatID",
    loadChildren: () =>
      import("./chats/messenger/messenger.module").then((m) => m.MessengerPageModule),
    resolve: {
      messages: MessagesResolver,
    },
  },

CodePudding user response：

Using a factory will allow you to access services, components, properties, functions, etc. when a specific service is created. This allows you to modify the creation process a little bit once the service is created such as assigning a value to a property.

@Component({
  providers: [{
    provide: MessagesService, 
    useFactory: (messageResolver: MessageResolver) => messageResolver.msgService, 
    deps: [MessageResolver]
  }]
})
export class MessengerComponent {

}