news.service.ts

import { Injectable } from '@angular/core';
import { News } from "../entity/news";
import {Http, Headers, Response} from '@angular/http';
import 'rxjs/add/operator/toPromise';
import {Observable} from 'rxjs/Rx';
import 'rxjs/add/operator/map';

@Injectable()
export class NewsService {
  private apiUrl = 'https://url.com';

  constructor(private http: Http) {
  }

  getAllNews() {
    return this.http.get(this.apiUrl)
        .map(res => res.json()[1].newsList);
  }

  getNews(): Promise<News[]> {
    return this.http.get(this.apiUrl)
        .toPromise()
        .then(response => response.json()[1].newsList as News[])
        .catch(this.handleError);
  }

  private handleError(error: any): Promise<any> {
    console.error('An error occurred', error);
    return Promise.reject(error.message || error);
  }

}