Accessing snapshots

The router exposes parameters and data as observables, which is convenient most of the time, but not always. Sometimes what we want is a snapshot of the state that we can examine at once.

@Component({...})
class MessageCmp {
  constructor(r: ActivatedRoute) {
    r.url.subscribe(() => {
      r.snapshot; // any time url changes, this callback is fired
    });
  }
}