How to set context on an Angular [cdkPortalOutlet]

The Portal module in Angular Material (CDK) is a very powerful way to render dynamic content into a 'PortalOutlet'.

A Portal<T> can be a TemplateRef where T is the type of the context data.

<ng-template cdkPortal let-data><p>Portal contents {{ data | json }}</p></ng-template>

You get a reference to it with @ViewChild

@ViewChild(CdkPortal) myPortalRef: CdkPortal;  

You can display a portal in a cdkPortalOutlet

Content gets inserted here: <ng-template [cdkPortalOutlet]="myPortalRef"></ng-template>

This will insert the portal contents into the outlet.

But there are two big missing features with the provided directives.

1) no way to set the actual context object on the outlet using the directive2) no way to set the context object on the portal itself

You can manually create an portal and provide a context, or attach a Portal to a PortalOutlet programatically with a context but I want to do it more declaratively.

The similar (and more commonly used) [NgTemplateOutlet] does provide a property for [ngTemplateOutletContext].

What's the best way to set context on a CdkPortal? Should I extend the directives myself, or try to pass through my data with a service? I thought the whole point of this module was to make things super easy.

Angular source

See also: https://github.com/angular/material2/issues/6310