如何从子组件中使用EventEmitter，并在父组件中使用observable (角度2)

import { Component, EventEmitter, Output } from '@angular/core';

@Component({
  selector: 'app-child',
  template: `
    <button (click)="emitData()">传递数据</button>
  `
})
export class ChildComponent {
  @Output() dataEvent = new EventEmitter<string>();

  emitData() {
    this.dataEvent.emit('Hello from child component');
  }
}

import { Component } from '@angular/core';
import { Observable } from 'rxjs';

@Component({
  selector: 'app-parent',
  template: `
    <app-child (dataEvent)="handleData($event)"></app-child>
    <div>{{ data$ | async }}</div>
  `
})
export class ParentComponent {
  data$: Observable<string>;

  handleData(data: string) {
    this.data$ = new Observable<string>((observer) => {
      observer.next(data);
    });
  }
}