createNotifier in a service

[jurck222]

Hello i have a question about createNotifier. I have an app that has a component called DataList in this component in use rxjs to make backend calls. I also have a child component of the DataList component called AddData where i add a new entry to the db. I then need to make a refetch in DataList to refresh the data. I was using computedAsync with a repeat operator and a subject to trigger the refetch from AddData component but i decided to start using a notifier to rereun computedAsync. The thing is i put the createNotifier in the service so it can be used by both DataList and AddData components DataList would listen and AddData would notify when a new entry was added. Is this considered bad practice?

Right now it looks something like this for DataListComponent:

@Component
export class DataListComponent{
  user = input.required();
  dataService = inject(DataService);
  userData = computedAsync(()=> {
    this.dataService.refetchNotifier.listen();
    return this.#fetchData(this.user().id); //function that makes the call to backend
  })
}

DataService:

@Injectable
export class DataService {
  readonly #http = inject(HttpClient);

  refetchNotifier = createNotifier();

  fetchUserData(userId: number): Observable<Data[]> {
    return this.#http.get<Data[]>(`${apiDataPath}/${userId}`);
  }

  addData(userId: number, data: Data): Observable<Data[]> {
    return this.#http.post<Data[]>(`${apiDataPath}/${userId}`, data);
  }
}

AddDataComponent:

@Component
export class AddDataComponent{
  user = input.required();
  dataService = inject(DataService);
  data: Data;  //Data comes from user input
  addData(userId){
    this.dataService.addData(this.user().id);
    this.dataService.refetchNotifier.notify();
  }
}

This is not my actual code and is just provided to show what im talking about. Sorry if my explanation was a bit rough.

[sysmat]

• I'm wondering the same, is good practice to have Notifier out side the component, so multiple components can listen Notifier
• motive would be to replace rxjs Subject in service as trigger for repeat some Observable

[eneajaho]

Hello @jurck222 @sysmat
Personally, I think both ways are fine. I'm doing both and haven't decided yet myself to only keep one or another. Do whatever works for you.

Btw, it's been 3 weeks since this was opened. What has worked well for you, and what not?

[jurck222]

Hello thank you for responding i stuck with the above mentioned method for now but only when necessary

[sysmat]

thx for response, yes it works fine in a service