getComponents(type: string): Observable<string[]> {
    return this.http.get('http://localhost:14373/api/devices/components/' + type)
       .map((response: Response) => response.json());
}

getComponentValues(type: string, component: string): Observable<string[]> {
   return this.http.get('http://localhost:14373/api/devices/components/' + type + '/' + component)
      .map((response: Response) => response.json());
}

ngOnInit() {
        this.subscription = this.route.params
            .subscribe(
                (params: any) => {
                    this.currentType = params['type'];
                    this.deviceService.getComponents(this.currentType).subscribe(
                        (data: string[]) => {
                            this.components = data;
                        }
                    );
                }
            );

    }

<div class="panel panel-default" *ngFor="let component of components">
    <!-- Default panel contents -->
    <div class="panel-heading">{{component}}</div>
    <!-- List group -->
    <ul class="list-group">
        <li class="list-group-item" *ngFor="let val of getComponentValues(currentType, component)">
            {{val}}
        </li>
    </ul>
</div>