如何订阅在代码的其他部分中发出的可观察对象？

import { Observable } from 'rxjs';

// 创建一个可观察对象
const myObservable = new Observable(observer => {
  observer.next('Hello');
  observer.next('World');
  setTimeout(() => {
    observer.next('Done!');
    observer.complete();
  }, 1000);
});

// 订阅可观察对象
const subscription = myObservable.subscribe({
  next(x) { console.log('got value ' + x); },
  error(err) { console.error('something wrong occurred: ' + err); },
  complete() { console.log('done'); }
});

// 取消订阅（可选）
setTimeout(() => {
  subscription.unsubscribe();
}, 1500);

myObservable.subscribe({
  next(x) { console.log('got value ' + x); },
  error(err) { console.error('Error:', err); },
  complete() { console.log('done'); }
});

const subscription = myObservable.subscribe({
  next(x) { console.log('got value ' + x); },
  complete() { console.log('done'); }
});

// 在适当的时候取消订阅
subscription.unsubscribe();

class MyComponent {
  private subscription: Subscription;

  ngOnInit() {
    this.subscription = myObservable.subscribe({
      next(x) { console.log('got value ' + x); },
      complete() { console.log('done'); }
    });
  }

  ngOnDestroy() {
    if (this.subscription) {
      this.subscription.unsubscribe();
    }
  }
}