<ion-content>

<ion-list *ngFor="let i of informations | async" >
  <ion-item (click)="OpenDetails(i.key)">{{i.title}}</ion-item>
</ion-list>

</ion-content>

import { Component } from '@angular/core';
import { NavController, NavParams } from 'ionic-angular';
import { AngularFireDatabase } from 'angularfire2/database';
import { InformationdetailsPage } from '../informationdetails/informationdetails';
import { map } from 'rxjs/operators';


@Component({
  selector: 'page-list',
  templateUrl: 'list.html'
})
export class ListPage {

  informationslist:any;
  informations:any;

  constructor(public navCtrl: NavController, public navParams: NavParams,
  private afDB: AngularFireDatabase) {



      this.informationslist = afDB.list('information');
      this.informations = this.informationslist.snapshotChanges().pipe(
        map(changes =>
        changes.map(c => ({ key: c.payload.key, ...c.payload.val() }))
        )
      );

  }

  OpenDetails(key:any){
    this.navCtrl.push(InformationdetailsPage, key);
  }



}

this.informations = this.informationslist.snapshotChanges().pipe(
    **map**(changes =>
    changes.map(c => ({ key: c.payload.key, ...c.payload.val() }))
    )
  );

import { map } from 'rxjs/operators';

this.informations = this.informationslist.snapshotChanges().pipe(
    map(changes =>
    changes.**map**(c => ({ key: c.payload.key, ...c.payload.val() }))
    )
  );