Interface that a class can implement to be a guard deciding if a child route can be activated. If all guards return true, navigation continues. If any guard returns false, navigation is cancelled. If any guard returns a UrlTree, current navigation is cancelled and a new navigation begins to the UrlTree returned from the guard.

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interface CanActivateChild {
  canActivateChild(childRoute: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<boolean | UrlTree> | Promise<boolean | UrlTree> | boolean | UrlTree
}

Description

The following example implements a CanActivateChild function that checks whether the current user has permission to activate the requested child route.

class UserToken {}
class Permissions {
  canActivate(user: UserToken, id: string): boolean {
    return true;
  }
}

@Injectable()
class CanActivateTeam implements CanActivateChild {
  constructor(private permissions: Permissions, private currentUser: UserToken) {}

  canActivateChild(
    route: ActivatedRouteSnapshot,
    state: RouterStateSnapshot
  ): Observable<boolean|UrlTree>|Promise<boolean|UrlTree>|boolean|UrlTree {
    return this.permissions.canActivate(this.currentUser, route.params.id);
  }
}

Here, the defined guard function is provided as part of the Route object in the router configuration:

@NgModule({
  imports: [
    RouterModule.forRoot([
      {
        path: 'root',
        canActivateChild: [CanActivateTeam],
        children: [
          {
             path: 'team/:id',
             component: TeamComponent
          }
        ]
      }
    ])
  ],
  providers: [CanActivateTeam, UserToken, Permissions]
})
class AppModule {}

You can alternatively provide an in-line function with the canActivateChild signature:

@NgModule({
  imports: [
    RouterModule.forRoot([
      {
        path: 'root',
        canActivateChild: ['canActivateTeam'],
        children: [
          {
            path: 'team/:id',
            component: TeamComponent
          }
        ]
      }
    ])
  ],
  providers: [
    {
      provide: 'canActivateTeam',
      useValue: (route: ActivatedRouteSnapshot, state: RouterStateSnapshot) => true
    }
  ]
})
class AppModule {}

Methods