message: feat(router): better warning message when a router outlet has not been instantiated
  It is confusing when routes are successfully activated but a component
  is not present on a page, with this message it's more clear.
  PR Close
diff: * found in the LICENSE file at https://angular.io/license
  */
  +import {isDevMode} from '@angular/core';
  import {MonoTypeOperatorFunction} from 'rxjs';
  import {map} from 'rxjs/operators';
  @@ -185,6 +186,10 @@ export class ActivateRoutes {
  // Activate the outlet when it has already been instantiated
  // Otherwise it will get activated from its `ngOnInit` when instantiated
  context.outlet.activateWith(future, cmpFactoryResolver);
  + } else if (isDevMode() && console && console.warn) {
  + console.warn(
  + `A router outlet has not been instantiated during routes activation. URL Segment: '${
  + future.snapshot._urlSegment}'`);
  }
  this.activateChildRoutes(futureNode, null, context.children);
  