The "authState" property does not exist in the "AngularFireAuth" type in an ionic 2 application

Question

I am trying to do facebook authentication using firebase AngularFire2. I follow the same steps as this tutorial github.com/angular/angularfire2/blob/master/docs/Auth-with-Ionic2.md

But for some reason this does not work. This gives me a lot of errors from my provider page. Here is my code.

import { Injectable } from '@angular/core';
import { Component } from '@angular/core';
import { Http } from '@angular/http';
import 'rxjs/add/operator/map';
import { Observable } from 'rxjs/Observable';
import { AngularFireAuth } from 'angularfire2/auth';
import * as firebase from 'firebase/app';


@Injectable()
export class AuthService {
     private authState: Observable<firebase.User>;
     private currentUser: firebase.User;

     constructor(public http: Http, public afAuth: AngularFireAuth) {
     console.log('Hello AuthService Provider');
     this.authState = afAuth.authState; //First error here.
     afAuth.subscribe((user: firebase.User) => { //second here
     this.currentUser = user;
      });
}

  get authenticated(): boolean {
    return this.currentUser !== null;
  }

  signInWithFacebook(): firebase.Promise<any> {
     return this.afAuth.auth.signInWithPopup(new firebase.auth.FacebookAuthProvider()); //third error here
      }

  signOut(): void {
    this.afAuth.signOut();
  }

  displayName(): string {
    if (this.currentUser !== null) {
      return this.currentUser.facebook.displayName;
       } else {
       return '';
       }
   }
}

Mistakes

Property 'authState' does not exist on type 'AngularFireAuth'.

Argument of type '(user: User) => void' is not assignable to parameter of type '(value: FirebaseAuthState) => void'. 
Types of parameters 'user' and 'value' are incompatible. 
Type 'FirebaseAuthState' is not assignable to type 'User'. 
Property 'delete' is missing in type 'FirebaseAuthState'.

Property 'auth' does not exist on type 'AngularFireAuth'.

I'm new to angular and ionic, please direct me here or go me a good tutorial

Answer 1

I will solve this problem by reinstalling Firebase and AngularFire2:

npm uninstall angularfire2 --save
npm uninstall firebase --save
npm install angularfire2 firebase --save