title: Ionic firebase send email verification
body: <p>I'm trying to send an email verification to the user when they sign up. The user gets added to firebase but the email is not sent. I logged the error to the console and it says </p>
  
  <blockquote>
    <p>Cannot read property 'sendEmailVerification' of undefined</p>
  </blockquote>
  
  <pre><code>import { Component } from '@angular/core';
  import { IonicPage, NavController, NavParams } from 'ionic-angular';
  import { User } from "../../models/user";
  import { AngularFireAuth } from "angularfire2/auth";
  import * as firebase from 'firebase';
  
  
  @IonicPage()
  @Component({
    selector: 'page-register',
    templateUrl: 'register.html',
  })
  export class RegisterPage {
  
    user = {} as User
  
    constructor(private afAuth: AngularFireAuth,
      public navCtrl: NavController, public navParams: NavParams) {
    }
  
    async register(user: User) {
       try {
         const result = await this.afAuth.auth.createUserWithEmailAndPassword(user.email, user.password)
         .then(res =&gt; {
           var auth = firebase.auth();
           this.auth.sendEmailVerification(user.email)
           this.navCtrl.setRoot('LoginPage');
         }
       }
       catch (e) {
         console.log(e);
       }
     }
  
  }
  </code></pre>