this-data.service.ts

import {Injectable, Inject} from "@angular/core";
import {Http} from "@angular/http";
import {Observable, BehaviorSubject} from "rxjs";

@Injectable()
export class ThisDataService {

  private thisData: BehaviorSubject<any[]> = new BehaviorSubject([]);
    
  public thisDataObs$: Observable<any[]> = this.thisData.asObservable();
    
  constructor (
    private http: Http
  ) {
    this.reloadThisData(); // if you want?
  }
    
  public reloadThisData() {
    this.http.get("this/data")
      .subscribe(d => this.thisData.next(d.json()))
  }
    
  public appendSomething(x: any) {
    this.thisData.next(this.thisData.value.concat(x));
  }

}