Question

我为Angular 4表单创建了一个canDeactivate处理程序。虽然这有效，但我担心我会导致内存泄漏（因为没有更好的术语）。我读到你必须取消订阅以避免不断增加的订阅列表;但是我不知道在哪里/如何取消订阅我在下面创建的订阅。 observer.complete调用是否会删除订阅？

  // Allow the user to navigate away from this page
  public canDeactivate(): Observable<boolean> {

    // Popup a prompt dialog
    const title = 'Lose Changes';
    const prompt = 'Are you sure you want to lose your changes?';
    this.dialogWindow.show(EDialogTypes.EDialogYesNo, EDialogStyles.EDialogStyleWarning, title, prompt);

    return Observable.create(observer => {
      this.dialogWindow.observable.subscribe(buttonPressed => {
        const proceed = (buttonPressed === EButtonPressed.EButtonPressedYes);
        console.log('Allow proceed: ' + proceed);
        observer.next(proceed);
        observer.complete();
      });
    });
  }

Answer 1

您可以将订阅保存到变量中，并在获得所需内容后使用它来取消订阅。像这样：

return Observable.create(observer => {
  let subscription = this.dialogWindow.observable.subscribe(buttonPressed => {
    const proceed = (buttonPressed === EButtonPressed.EButtonPressedYes);
    console.log('Allow proceed: ' + proceed);
    observer.next(proceed);
    observer.complete()
    subscription.unsubscribe(); // here you unsubscribe
  });
});

在观察者中删除订阅

1 个答案: