问当我尝试使用angular guard根据用户角色进行路由时，浏览器冻结

EN

export class AuthGuard implements CanActivate {
constructor(private auth: AuthService,
    private router: Router) { }
canActivate(
next: ActivatedRouteSnapshot,
state: RouterStateSnapshot): Observable<boolean> | Promise<boolean> | 
boolean {
console.log(this.auth.isLoggedIn())
if (this.auth.isLoggedIn()) {
  return true;
}  

this.router.navigate(['/login'], { queryParams: { returnUrl: state.url } })
return false;
}
}

export class RoleGuard implements CanActivate {
  constructor(private _auth: AuthService, private _router: Router) { }

canActivate(
next: ActivatedRouteSnapshot,
state: RouterStateSnapshot): Observable<boolean> | Promise<boolean> | boolean {
switch (this._auth.getRole()) {
  case "STUDENT":
    this._router.navigate(['/']);
    return true;
  case "DEPARTMENT":
    this._router.navigate(['/department']);
    return true;
  case "FACULTY":
    this._router.navigate(['/faculty']);
    return true;
  default:
    return false;
   }
  }
}

{ path: '', component: DashboardComponent, canActivate: [AuthGuard, RoleGuard] },
  { path: 'dashboard', component: DashboardComponent, canActivate: [AuthGuard, RoleGuard] }