使用Angular 4检查Web中的互联网连接

问题描述

我正在使用Angular 4进行应用程序开发.我需要检查使用Angular的网络连接是否可用. Angular 4有可能吗?

I am using Angular 4 for my application development. I need to check If the network connection is available for its have any Connection issue using Angular for. Is it possible with Angular 4.

我用https://github.com/HubSpot/offline检查过.我认为这不适用于角度为4的任何人.请提出任何建议.可以将Offlinejs用于Angular 4或任何其他替代方法吗?

I checked with https://github.com/HubSpot/offline . I think this will not work for angular 4. Any one please suggest. Is this possible to use offlinejs for Angular 4 or any other alternatives?

谢谢萨拉斯(Sarath)C M

ThanksSarath C M

推荐答案

我们不需要任何库，但是public onlineOffline: boolean = navigator.onLine;可以解决问题，但这只是一次检查.我们需要将此值视为可观察的值，因此，每当在线状态发生变化时，我们都会进行更新.为此，rxjs会有所帮助.

We don't need any libraries for this however public onlineOffline: boolean = navigator.onLine; will do the trick but this is just a one time check. We need to treat this value as an observable so whenever the online status change we are updated. For this rxjs will help.

导入这些

import { Observable, Observer, fromEvent, merge } from 'rxjs';
import { map } from 'rxjs/operators';

添加此方法

  createOnline$() {
    return merge<boolean>(
      fromEvent(window, 'offline').pipe(map(() => false)),
      fromEvent(window, 'online').pipe(map(() => true)),
      new Observable((sub: Observer<boolean>) => {
        sub.next(navigator.onLine);
        sub.complete();
      }));
  }

通过您的构造函数或ngOnInit订阅此事件

Subscribe to this event from your constructur or ngOnInit

this.createOnline$().subscribe(isOnline => console.log(isOnline));

注意:我正在使用 Angular 8.1 和 rxjs 6.5.2

Note: Im using Angular 8.1 and rxjs 6.5.2

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