app.component.ts

import { Component, ViewChild } from '@angular/core';
import { Nav, Platform } from 'ionic-angular';
import { StatusBar } from '@ionic-native/status-bar';
import { SplashScreen } from '@ionic-native/splash-screen';

// Import page components and authentication provider
import { HomePage } from '../pages/home/home';
import { ListPage } from '../pages/list/list';
import { LoginPage } from '../pages/login/login';
import { AuthProvider } from '../providers/auth/auth';

@Component({
  templateUrl: 'app.html'
})
export class MyApp {
  @ViewChild(Nav) nav: Nav;

  /**
   * Set the root page for the application
   */
  public rootPage: any = LoginPage;

  /**
   * Define the pages for the application
   */
  private pages: Array<{title: string, component: any}>;

  constructor(
    public platform: Platform,
    public statusBar: StatusBar, 
    public splashScreen: SplashScreen,
    private _AUTH: AuthProvider
  ) {
    this.initializeApp();

    // Populate pages for the application
    this.pages = [
      { title: 'Home', component: HomePage },
      { title: 'List', component: ListPage },
      { title: 'Logout', component: LoginPage}
    ];
  }

  /**
   * Initialise the application 
   * @method initializeApp
   * return { none }
   */
  initializeApp(): void {
    this.platform.ready().then(() => {
      // Okay, so the platform is ready and our plugins are available.
      // Here you can do any higher level native things you might need.
      this.statusBar.styleDefault();
      this.splashScreen.hide();
    });
  }

  /**
   * Open a page from the sidemenu
   * @method openPage
   * @param page  { object }
   * return { none }
   */
  openPage(page: any): void {
    // Ensure we can log out of Firebase and reset the root page
    if(page == 'LogOut') {
      this._AUTH.logOut().then((data: any) => {
        this.nav.setRoot(page.component);
      }).catch((error: any) => {
        console.dir(error);
      });
    }

    // Otherwise reset the content nav to have just this page
    // we wouldn't want the back button to show in this scenario
    else {
      this.nav.setRoot(page.component);
    }
  }
}