D-Net

import { filter, switchMap, tap } from 'rxjs/operators';

import { AuthService } from './../services/auth.service';

import { Injectable } from '@angular/core';

import { CanActivate, ActivatedRouteSnapshot, RouterStateSnapshot, UrlTree, Router } from '@angular/router';

import { Observable } from 'rxjs';

@Injectable({

  providedIn: 'root'

})

export class AuthGuard implements CanActivate {

  constructor(private auth: AuthService, private router: Router) { }

  canActivate(

    route: ActivatedRouteSnapshot,

    state: RouterStateSnapshot): Observable<boolean | UrlTree> | Promise<boolean | UrlTree> | boolean | UrlTree {

    return this.auth.isDoneLoading$.pipe(

      filter(isDone => isDone),

      switchMap(_ => this.auth.isAuthenticated$),

      tap(isAuthenticated => isAuthenticated || this.auth.login(state.url)),

    );

  }

}