Example:
[code type=javascript]
import { Events } from ‘ionic-angular’;

export class BasePage {

constructor(public eventsCtrl: Events) { }

ionViewDidEnter() {
this.eventsCtrl.publish(‘page:load’);
}

ionViewDidUnload() {
this.eventsCtrl.publish(‘page:unload’);
}
}

Referência

From a tab page you can do:

[code type=javascript]this.nav.parent.parent.setRoot(LoginPage);

Before:

Nav -> Tabs -> somepage

After:

Nav -> LoginPage

Nav is the root of all nav stacks in Ionic 2.

Referência