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CanDeactivate

npm Package @angular/router
Module import { CanDeactivate } from '@angular/router';
Source router/src/interfaces.ts

Interface that a class can implement to be a guard deciding if a route can be deactivated.

Interface Overview

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

How To Use

      
      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>|Promise<boolean>|boolean {
    return this.permissions.canDeactivate(this.currentUser, route.params.id);
  }
}

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

Members

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