Setting root page in ionic2 and angular2 app based on an asynchronous event

Question

I'm trying to start a basic ionic2 app and was wondering if my timing of initial app loading is a problem or not. What I'd like to do is set the start page to a login page if the user is not authenticated.

I originally set the rootpage to the home page and then when the async call came back from localstorage, I would then reset the rootpage to the login page if the user was unauthenticated. However, this caused a flickering where they see one page and then get sent to another page.

It seems like what I want to do is wait for the local storage call before I show any screen.

My question is this: as the code stands now, will there be an error condition where the platform ready fires before the root page is set, thus causing some sort of problem? How should I handle this situation in Ionic 2 and Angular 2? Should I make the get localStorage call synchronous, or should I stuff it in another event or method that is part of the app or page lifecycle in Angular 2?

Should I use some sort of observable or await syntax?

export class MyApp {
  rootPage: any;
  local: Storage = new Storage(LocalStorage);

  constructor(platform: Platform) {

    this.local.get('user').then(user => {
      if (user) {
        this.rootPage = TabsPage;
      } else {
        this.rootPage = LoginPage;
      }
    });

    platform.ready().then(() => {
      // Will this ever fire before the rootpage is set?
      StatusBar.styleDefault();

    });
  }
}

Answer 1

You don't need to add asynchronous call to the local storage as you can see in this example: https://github.com/RedFroggy/ionic2-nfc-app/blob/master/app/app.ts#L52

You just need to check the user existence in the local storage and set the rootPage to the HomePage or LoginPage.

Answer 2

You could create dummy initial page (i.e. white background, preloader whatever) to avoid flickering and then switch to login or tabs page.