Ionic 2 problem files

problem.html

<ion-header>
    <ion-navbar news>
        <button menuToggle>
            <ion-icon name="menu"></ion-icon>
        </button>
        <ion-title>Neuigkeiten</ion-title>
        <ion-buttons end>
            <button (click)="newPost()">
                <ion-icon name="add"></ion-icon>
            </button>
        </ion-buttons>
    </ion-navbar>
</ion-header>
<pan-newsfeed [news]="news | async" [users]="users | async" [self]="self | async" (scrollEnd)="doInfinite($event)"
              (modifyPost)="modifyPost($event)" (newComment)="newComment($event)"></pan-newsfeed>
              
              
              
<!--============COMPONENT VIEW============-->
<ion-content padding class="feed" class="grey">
    <div>
        <ion-card *ngFor="let item of news">
            <ion-item>
                <ion-avatar item-left>
                    <img src="https://auszubildenden-netzwerk.de/assets/user_images/{{item.user_id}}.jpg">
                </ion-avatar>
                <h2>{{users[item.user_id].name}} {{test}}</h2>
                <p>{{item.date | time}}</p>
            </ion-item>
            <div *ngFor="let file of item.files">
                <a href="#" (click)="open('https://auszubildenden-netzwerk.de/files/'+file._id+'.'+file.type)"
                   style="margin-bottom: 5px;"><img *ngIf="['jpg','gif','png'].indexOf(file.type.toLowerCase())!=-1"
                                                    src="https://auszubildenden-netzwerk.de/files/thumbs/{{file._id}}.{{file.type}}"
                                                    style="margin-bottom: 5px;"></a>
            </div>
            <ion-card-content>
                <p>{{item.text}}</p>
                <ion-list>
                    <ion-list-item *ngFor="let file of item.files">
                        <a *ngIf="['jpg','gif','png', 'jpeg'].indexOf(file.type.toLowerCase())==-1" href="#"
                           (click)="open('https://auszubildenden-netzwerk.de/files/'+file._id+'.'+file.type)">{{file._id}}.{{file.type}}</a>
                    </ion-list-item>
                </ion-list>
            </ion-card-content>
            <hr>
            <ion-row class="post-data">
                <div (click)="showPopover($event, item.likes)">Gefällt {{item.likes.length}}</div>
                <div (click)="toggleComments(item)">{{item.comments.length}} {{item.comments.length == 1 ? 'Kommentar' :
                    'Kommentare' }}
                </div>
                <div (click)="showPopover($event, item.seen)">Gesehen von {{item.seen.length}}</div>
            </ion-row>
            <hr style="margin-bottom: -5px;">
            <ion-row>
                <ion-col>
                    <button grey clear small (click)="likePost(item)" *ngIf="item.likes.indexOf(self._id) == -1">
                        <ion-icon name="thumbs-up"></ion-icon>
                        <div>Gefällt mir</div>
                    </button>
                    <button primary clear small (click)="likePost(item)" *ngIf="item.likes.indexOf(self._id) != -1">
                        <ion-icon name="thumbs-up"></ion-icon>
                        <div>Gefällt mir</div>
                    </button>
                </ion-col>
                <ion-col width-100></ion-col>
                <ion-col>
                    <button grey clear small (click)="addComment(item)">
                        <ion-icon name="text"></ion-icon>
                        <div>kommentieren</div>
                    </button>
                </ion-col>
            </ion-row>
            <ion-list *ngIf="item.showComments">
                <ion-item *ngFor="let comment of item.comments" text-wrap>
                    <ion-avatar item-left>
                        <img src="https://auszubildenden-netzwerk.de/assets/user_images/{{comment.user_id}}.jpg">
                    </ion-avatar>
                    <h2>{{users[comment.user_id].name}}
                        <small>{{comment.date | time}}</small>
                    </h2>
                    <p>{{comment.text}}</p>
                </ion-item>
            </ion-list>
        </ion-card>
    </div>
    <ion-infinite-scroll (ionInfinite)="doInfinite($event)">
        <ion-infinite-scroll-content>
            Lade mehr posts ...
        </ion-infinite-scroll-content>
    </ion-infinite-scroll>
</ion-content>