Multiple instantiations of singleton service in angular 6

Issue

I have an angular service provided in root

import {Injectable} from "@angular/core";
import {BehaviorSubject} from "rxjs";
import {Admin} from "../models/admin.model";
import {AdminsService} from "./admins.service";

@Injectable({
  providedIn: 'root'
})
export class CurrentUserService {
  public user$: BehaviorSubject<Admin> = new BehaviorSubject(null);

  constructor(private _adminsService: AdminsService) {
    console.log('current user service instantiated');
    this._adminsService.getCurrentUser()
      .subscribe(user => {
        this.user$.next(user);
      });
  }

  public update() {
    this._adminsService.getCurrentUser().subscribe(user => {
      this.user$.next(user);
    })
  }

  public clear() {
    this.user$.next(null);
  }
}

I provide it and Http Interceptor in app.module in this way:

providers: [
    CurrentUserService,
    {
      provide: HTTP_INTERCEPTORS,
      useClass: AuthInterceptor,
      multi: true
    }
  ],

And when I try to inject it into interceptor i get a lot of messages from constructor, that indicates that service instantiates many times. Can anybody explain this behavior and may be have some idea of how to fix it?

console with messages screenshot

Solution

This is because of you are providing the same service multiple times in the same module -

First by

@Injectable({
  providedIn: 'root'
})

Second by

providers: [
    CurrentUserService,
    {
      provide: HTTP_INTERCEPTORS,
      useClass: AuthInterceptor,
      multi: true
    }
  ],

Better you remove from the first one.

Answered By - Sunil Singh