export class AfterViewComponent implements  AfterViewChecked, AfterViewInit {
	private prevHero = '';

	// Query for a VIEW child of type `ChildViewComponent`
	@ViewChild(ChildViewComponent) viewChild: ChildViewComponent;

	ngAfterViewInit() {
		// viewChild is set after the view has been initialized
		this.logIt('AfterViewInit');
		this.doSomething();
	}

	ngAfterViewChecked() {
		// viewChild is updated after the view has been checked
		if (this.prevHero === this.viewChild.hero) {
			this.logIt('AfterViewChecked (no change)');
		} else {
			this.prevHero = this.viewChild.hero;
			this.logIt('AfterViewChecked');
			this.doSomething();
		}
	}
// ...
}