news.page.ts

import { Component, OnInit } from '@angular/core';
import { Router } from '@angular/router';
import { Observable } from 'rxjs';
import {AngularFirestore} from 'angularfire2/firestore';

      @Component({
        selector: 'app-news',
        templateUrl: './news.page.html',
        styleUrls: ['./news.page.scss']
      })
      export class NewsPage implements OnInit {
        data: any;
        constructor(public db: AngularFirestore, private router: Router) {}

        ngOnInit() {
            this.getAllPosts().subscribe((data)=>{
                this.data = data;
                console.log(data);
            });
        }

        getPostEntry ( postTitle: string ): Observable<any> {
            return this.db.collection<any> ( "posts" , ref => ref.where ( 'title' , '==' , postTitle ) ).valueChanges ();
        }

        getAllPosts (): Observable<any> {
            return this.db.collection<any>( "post" ).valueChanges ();
        }

        onGoToNewsSinglePage(article) {
          //this.newsService.currentArticle = article;
          //this.router.navigate(['/news-single']);
        }
    }