Changing ion-navbar dynamically

<ion-nav-bar> is the v1 component for a navbar. For v2 it is <ion-navbar>. This is not currently possible if you don't know the attribute name in advance, but yes it is something we need to support.

For example, if you know you want to add primary when true but don't add it all otherwise, you can do:

<ion-navbar [attr.primary]="true ? '' : null">

Open issue on Angular for this here: https://github.com/angular/angular/issues/5361#issuecomment-159363377