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/Angular 7

CanDeactivate

interface

Interface that a class can implement to be a guard deciding if a route can be deactivated. If all guards return true, navigation will continue. If any guard returns false, navigation will be cancelled. If any guard returns a UrlTree, current navigation will be cancelled and a new navigation will be kicked off to the UrlTree returned from the guard.

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interface CanDeactivate<T> {
  canDeactivate(component: T, currentRoute: ActivatedRouteSnapshot, currentState: RouterStateSnapshot, nextState?: RouterStateSnapshot): Observable<boolean | UrlTree> | Promise<boolean | UrlTree> | boolean | UrlTree
}

Description

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

@Injectable()
class CanDeactivateTeam implements CanDeactivate<TeamComponent> {
  constructor(private permissions: Permissions, private currentUser: UserToken) {}

  canDeactivate(
    component: TeamComponent,
    currentRoute: ActivatedRouteSnapshot,
    currentState: RouterStateSnapshot,
    nextState: RouterStateSnapshot
  ): Observable<boolean|UrlTree>|Promise<boolean|UrlTree>|boolean|UrlTree {
    return this.permissions.canDeactivate(this.currentUser, route.params.id);
  }
}

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

You can alternatively provide a function with the canDeactivate signature:

@NgModule({
  imports: [
    RouterModule.forRoot([
      {
        path: 'team/:id',
        component: TeamComponent,
        canDeactivate: ['canDeactivateTeam']
      }
    ])
  ],
  providers: [
    {
      provide: 'canDeactivateTeam',
      useValue: (component: TeamComponent, currentRoute: ActivatedRouteSnapshot, currentState:
RouterStateSnapshot, nextState: RouterStateSnapshot) => true
    }
  ]
})
class AppModule {}

Methods

canDeactivate(component: T, currentRoute: ActivatedRouteSnapshot, currentState: RouterStateSnapshot, nextState?: RouterStateSnapshot): Observable<boolean | UrlTree> | Promise<boolean | UrlTree> | boolean | UrlTree

Parameters
component T
currentRoute ActivatedRouteSnapshot
currentState RouterStateSnapshot
nextState RouterStateSnapshot

Optional. Default is undefined.

Returns

Observable<boolean | UrlTree> | Promise<boolean | UrlTree> | boolean | UrlTree

© 2010–2019 Google, Inc.
Licensed under the Creative Commons Attribution License 4.0.
https://v7.angular.io/api/router/CanDeactivate