Rxjs计时器带有暂停并恢复轮询

时间:2018-11-05 22:21:50

标签: javascript angular typescript rxjs rxjs6

我有一项服务HomeService,并且该服务中有此方法

getAlerts(): Observable<any> {
    return this.apiService.post(`${this.DASHBOARD_URL}/alerts`);
}

因此,我有一个场景,我必须每10秒轮询一次此方法以获取新数据,并且轮询仅应在成功响应以及浏览器选项卡处于活动状态时进行。当浏览器选项卡处于非活动状态时,轮询应暂停并在选项卡处于活动状态时恢复。

我正在从组件中执行此操作:

import {Subscription, timer as observableTimer} from 'rxjs';
import {delay, retryWhen, takeWhile} from 'rxjs/operators';

    private pollAlerts(): void {
             this.pollAlertsRequest = this.homeService.getAlerts().pipe(retryWhen(errors => errors.pipe(delay(10 * 1000))))
              .subscribe(res => {
                this.populateAlerts(res.alerts);
                this.alertsTimer = observableTimer(10 * 1000).pipe(
                  takeWhile(() => this.isComponentAlive))
                  .subscribe(() => {
                    this.pollAlerts();
                  });
              });
    }

我能够完成计时器,但不确定如何暂停和继续。

1 个答案:

答案 0 :(得分:0)

更改takeWhile进行过滤

private pollAlerts(): void {
             this.pollAlertsRequest = this.homeService.getAlerts().pipe(retryWhen(errors => errors.pipe(delay(10 * 1000))))
              .subscribe(res => {
                this.populateAlerts(res.alerts);
                this.alertsTimer = observableTimer(10 * 1000).pipe(
                  filter(() => this.isComponentAlive)),
                  switchMap(()=>interval(1000)),
                     tap(()=>this.pollAlerts());
                 ).subscribe();
              });