Injecting services best practises

[AaronSterling]

private _example: BehaviorSubject<number> = new BehaviorSubject<number>(5);

// update example
this._example.next(6);

// method exposed in provider for pages to use
exampleStream(): Observable<number> {
  return this._example.asObservable();
}

// in a page
exampleLocalCopy: number;
this.exampleProvider.exampleStream().subscribe(ex => this.exampleLocalCopy = ex);