a82fddf1ce
This PR formalizes, documents, and makes public the router outlet contract. The set of `RouterOutlet` methods used by the `Router` has not changed in over 4 years, since the introduction of route reuse strategies. Creation of custom router outlets is already possible and is used by the Ionic framework (https://github.com/ionic-team/ionic-framework/blob/master/angular/src/directives/navigation/ion-router-outlet.ts). There is a small "hack" that is needed to make this work, which is that outlets must register with `ChildrenOutletContexts`, but it currently only accepts our `RouterOutlet`. By exposing the interface the `Router` uses to activate and deactivate routes through outlets, we allow for developers to more easily and safely extend the `Router` and have fine-tuned control over navigation and component activation that fits project requirements. PR Close #40827
Angular Router
Managing state transitions is one of the hardest parts of building applications. This is especially true on the web, where you also need to ensure that the state is reflected in the URL. In addition, we often want to split applications into multiple bundles and load them on demand. Doing this transparently isn’t trivial.
The Angular router is designed to solve these problems. Using the router, you can declaratively specify application state, manage state transitions while taking care of the URL, and load components on demand.
Guide
Read the dev guide here.