Angular 2 Firebase auth guard

auth.guard.ts

import { Injectable } from '@angular/core';
import { CanActivate, Router } from '@angular/router';

import { FirebaseAuth, FirebaseAuthState } from 'angularfire2';
import { Observable } from 'rxjs/Observable';

@Injectable()
export class AuthGuard implements CanActivate {

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

  canActivate(): Observable<boolean> {
    return this.auth.take(1)
    .map((authState: FirebaseAuthState) => !!authState)
    .do(authenticated => {
      if (!authenticated) {
        this.router.navigate(['/login']);
      }
    });
  }
}

it doesn't work

here is the work code

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

import { AngularFireAuth } from 'angularfire2/auth';
import {Observable} from "rxjs/Observable";
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/take';
import 'rxjs/add/operator/do';

@Injectable()
export class AuthGuard implements CanActivate {

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

canActivate(): Observable<boolean> {
    return this.auth.authState
        .take(1)
        .map(authState => !!authState)
        .do(auth => !auth ? this.router.navigate(['/login']) : true);
}

Or for RXJS 6+

return this.auth.authState.pipe(
      take(1),
      map(authState => !!authState),
      tap(auth => !auth ? this.router.navigateByUrl('/login') : true)
  )