[destus]

Это в userService

public isAuthenticated(): Observable<boolean> {    
	return this.getUser().pipe(
		map(data => !!data['login'])
	);
}

это в authGuard

canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot) : Observable<boolean>{
	return this.userService.isAuthenticated().pipe(
		tap((isAuthenticated: boolean) => {
			if (!isAuthenticated) {
				this.router.navigate(['/login'])
			}
		})
	);
}