Ionic2 - check if page is active

Question

How can I check if a ionic2 page is active?

For example I want to hide a button if a page is active:

<button primary [hidden]="isActive('actualPageName')">
     Should be hidden
</button>

Answer 1

IONIC 2 & 3: Because of the uglification you cannot use pagename for production.

I check the active page by looking if the last page on the controller stack is of the instance of the page:

import { NavController } from 'ionic-angular';
import { myPage } from '../../pages/my/my';
...
constructor(public navCtrl: NavController) {}
...
let active = this.navCtrl.last().instance instanceof MyPage;

IONIC 4: Routing is changed. This looks like the new way:

import { Router } from '@angular/router';
...
constructor(public router: Router) {}
...
let active =  this.router.isActive('mypage', false)