Angular: event emmiter

App.ts

/** *** */
@Component({
  ...
  template: `
  <div>
     ...
     <button (click)="mutateProps()">Mutate!</button>
  </div>
  `,
})
export class NewsComponent  {
  ...
  @Output() changeTitle: EventEmitter<any> = new EventEmitter();
  mutateProps() {
    this.changeTitle.emit("Title changed!")
  };
}

/** *** */
<news ... (changeTitle)="changeTitle($event)"></news>

<button (click)="printState()">Print parent state</button>

/** *** */
export class AppComponent  {
  ...
  changeTitle(event) {
    this.title = event;
  }
  printState() {
    console.log(`News title: ${this.title}, News content: ${this.content}`);
  }
}