使用间隔时如何立即启动Angular 2 Observable [英] How to start immediately an Angular 2 Observable when using interval

问题描述

我有以下 Angular 2 服务，该服务每5秒获取一次数据:

I have the following Angular 2 service that is fetching data every 5 seconds:

import { Observable } from "rxjs/Rx";
import { Http, Response } from '@angular/http';


@Injectable()
export class DataService{
  getData():{
    return Observable
        .interval(5000)
        .flatMap(() => this.http.get('http://some_url'))
        .map((res: Response) => res.json())
  }

是否有一种方法可以使此服务在开始时执行请求?否则，它将在第一次执行之前等待5秒钟.

Is there a way to have this service executing the request at the start? Otherwise it will wait for 5 seconds before the first execution.

推荐答案

将interval替换为

Replace interval with timer, as it allows you to specify an initial delay:

getData():{
  return Observable
    .timer(0, 5000)
    .flatMap(() => this.http.get('http://some_url'))
    .map((res: Response) => res.json())
}

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