feat(router): add ability to unregister a route (#60)

Closes #49

README.md

@@ -26,7 +26,7 @@ yarn add angular-routing
 
 ## Installation with ng add
 
-You can use ng add to install the package by using below command.
+You can use ng add to install the package by using the command below.
 
 ```sh
 ng add angular-routing
@@ -85,6 +85,62 @@ After your components are registered, use the `Router` and `Route` components to
 </router>
 ```
 
+## Route sorting
+
+Angular routing is sorting the routes upon registration, based on priority. The order in which the routes are defined in your template is therefore not important.
+
+The following two examples will give the same results
+
+```html
+<router>
+  <route path="/blog" [exact]="false">
+    <app-blog *routeComponent></app-blog>
+  </route>
+  <route path="/" redirectTo="/blog"></route>
+  <route path="/" [exact]="false">
+    <app-page-not-found *routeComponent></app-page-not-found>
+  </route>
+</router>
+```
+
+and
+
+```html
+<router>
+  <route path="/" [exact]="false">
+    <app-page-not-found *routeComponent></app-page-not-found>
+  </route>
+  <route path="/" redirectTo="/blog"></route>
+  <route path="/blog" [exact]="false">
+    <app-blog *routeComponent></app-blog>
+  </route>
+</router>
+```
+
+The sorting algorithm has only a few rules (ordered by importance):
+
+- Named routes (e.g. `/blog`) have priority over root route (`/`)
+- Static routes (e.g. `/blog/view`) have priority over parametrized (e.g. `/blog/:id`)
+- Exact route (with `exact` set to `true` or omitted) has priority over non-exact (with `exact` set to `false`)
+- Longer paths have priority over shorter
+
+## Route restrictions
+
+Implementing the route restriction is as simple as adding a structural directive on a `route` component
+
+```html
+<router>
+  <route path="/admin" *ngIf="user.isAuthenticated$ | async">
+    <app-admin *routeComponent></app-admin>
+  </route>
+  <route path="/admin" *ngIf="!(user.isAuthenticated$ | async)">
+    <app-login *routeComponent></app-login>
+  </route>
+</router>
+```
+
+The restriction doesn't stop the navigation. It simply removes the route from the configuration so the next eligible route will pick it up.
+
 ## Navigating with Links
 
 Use the `linkTo` directive with a _full path_ to register links handled by the router.

libs/angular-routing/src/lib/route.component.ts

@@ -161,6 +161,7 @@ export class RouteComponent implements OnInit, OnDestroy {
   }
 
   ngOnDestroy() {
+    this.routerComponent.unregisterRoute(this.route);
     this.destroy$.next();
   }
 

libs/angular-routing/src/lib/router.component.ts

@@ -26,6 +26,8 @@ interface State {
   routes: Route[];
 }
 
+type UnregisterableRoute = Route & { unregister?: boolean };
+
 @Component({
   // tslint:disable-next-line:component-selector
   selector: 'router',
@@ -115,9 +117,7 @@ export class RouterComponent implements OnInit, OnDestroy {
     });
 
     route.matcher = route.matcher || routeRegex;
-
-    const routes = this.state$.value.routes;
-    this.updateState({ routes: routes.concat(route).sort(compareRoutes) });
+    this.updateRoutes(route);
 
     return route;
   }
@@ -126,6 +126,10 @@ export class RouterComponent implements OnInit, OnDestroy {
     this.updateState({ activeRoute });
   }
 
+  unregisterRoute(route: Route) {
+    this.updateRoutes({ ...route, unregister: true });
+  }
+
   normalizePath(path: string) {
     return this.router.normalizePath(path);
   }
@@ -155,4 +159,15 @@ export class RouterComponent implements OnInit, OnDestroy {
   private updateState(newState: Partial<State>) {
     this.state$.next({ ...this.state$.value, ...newState });
   }
+
+  private updateRoutes(route: UnregisterableRoute) {
+    const routes = this.state$.value.routes;
+    if (route.unregister) {
+      this.updateState({
+        routes: routes.filter((r) => r.matcher !== route.matcher),
+      });
+    } else {
+      this.updateState({ routes: routes.concat(route).sort(compareRoutes) });
+    }
+  }
 }