angular - 行为主题 : ignore last value if next() didn't triggered

Question

在我的应用程序中，我使用 BehaviorSubject 将数据从提供程序传递到页面组件:

工作管理器

  private futureJobsSource = new BehaviorSubject <Array<Job>>([]);
  futureJobsUpdate = this.futureJobsSource.asObservable();

源更新的地方:

 getFutureJobs(date: string) {
//
//
this.api.getFutureJobs(request).subscribe((res) => {
      console.log(this.TAG + 'getFutureJobs: success: ' + JSON.stringify(res));
      this.futureJobsSource.next(res);
    }, (err) => {
      console.log(this.TAG + 'getFutureJobs: failure: ' + JSON.stringify(err));
      this.message.showErrorAlert(err.detail);
    });
}

还有我的组件，FutureJobsPage

 setSearchDate() {
    DatePicker.show(this.datePickerOptions).then((date) => {
      this.jobsManager.getFutureJobs(moment(date).format('MM/DD/YYYY'));
    });
  }

ionViewDidLoad() {
    console.log('ionViewDidLoad FutureJobsPage');
    this.subscription = this.jobsManager.futureJobsUpdate.subscribe((res) => {
      console.log(this.TAG + 'subscribe: ' + JSON.stringify(res));
      this.futureJobs = res;
    });
  }

 ionViewDidLeave() {
   console.log(this.TAG + 'ionViewDidLeave');
   this.jobsManager.futureJobsUpdate.distinctUntilChanged();
   this.subscription.unsubscribe();
   this.futureJobs = [];
 }

我从搜索中了解到从提供者 BehaviorSubject 传递数据的正确方法是一个最佳解决方案，但如果不是来自 next()，我想忽略最后接收到的值。实现这种行为的最佳做法是什么？

Answer 1

使用Subject代替BehaviorSubject，订阅只会在第一次发出后开始。

行为主题

One of the variants of Subjects is the BehaviorSubject, which has a notion of "the current value". It stores the latest value emitted to its consumers, and whenever a new Observer subscribes, it will immediately receive the "current value" from the BehaviorSubject.

希望这对您有所帮助!