Add class to body on Angular2

Question

I have three components. These are HomeComponent, SignInComponent and AppComponent. My Home Page (HomeComponent) is showing when the application opened. I clicked the \"Sign

Answer 1

You can change your root selector to body and then use HostBinding decorator

@Component({
  selector: 'body',
  template: ``
})
export class AppComponent {
  @HostBinding('class') public cssClass = 'class1';
}

@Component({
  selector: 'child',
  template: `Set class`
})
export class ChildComponent {
  constructor(private rootComp: AppComponent) {  }
  setClass() {
    this.rootComp.cssClass = 'class2';
  }
}