You can switch to the latest version Angular 7.
Acts as a placeholder that Angular dynamically fills based on the current router state.
<router-outlet></router-outlet> <router-outlet name='left'></router-outlet> <router-outlet name='right'></router-outlet>
A router outlet will emit an activate event any time a new component is being instantiated, and a deactivate event when it is being destroyed.
<router-outlet (activate)='onActivate($event)' (deactivate)='onDeactivate($event)'></router-outlet>