在外部可观察对象上添加.pipe(takeUntil(this.destroy$))即可解决。

代码示例：

import { Component, OnDestroy } from '@angular/core';
import { Subject, Observable, interval } from 'rxjs';
import { switchMap, takeUntil } from 'rxjs/operators';

@Component({
  selector: 'app-example',
  template: `
    Start
    Stop
  `,
})
export class ExampleComponent implements OnDestroy {
  private readonly destroy$ = new Subject();

  start() {
    interval(1000)
      .pipe(
        takeUntil(this.destroy$),
        switchMap(() => this.getData())
      )
      .subscribe({
        next: value => console.log(value),
        error: error => console.error(error),
      });
  }

  stop() {
    this.destroy$.next();
    this.destroy$.complete();
  }

  getData(): Observable {
    return new Observable(observer => {
      observer.next('Data');
      observer.complete();
    });
  }

  ngOnDestroy() {
    this.destroy$.next();
    this.destroy$.complete();
  }
}