Javascript Service worker onload 显示通知

Question

我有一个已注册的服务 worker ，但我想循环一个函数来检查服务器上的更新并显示通知，即使在选项卡关闭时也是如此。

在 serviceworker.js 中使用以下代码，我得到一个错误；“未捕获( promise )TypeError:ServiceWorkerRegistration 上没有可用的事件注册。”

self.registration.showNotification(title, {
        body: 'We have received a push message',
        icon: '',
        tag: ''
})

我希望在打开浏览器时弹出通知，就像 Facebook 那样。

Answer 1

嗯，你需要先了解 service-worker 的生命周期

    // listen for a push notification from gcm, as only it can reiterate 
    // your push-notifications to your clients subscriber id
    // put your code inside listener

       self.addEventListener('push', function(event) {  
          console.log('Received a push message', event);

         // here you can make rest calls to fetch data against the subscriber-id 
         // and accordingly, set data 
         // keep in mind that your server sends push notifications to gcm
         // and then your subscribers receive them here

         var title = 'title' || 'data-from-rest-call';  
         var body = 'body' || 'data-from-rest-call';  
         var icon = '/your image path' || 'data-from-rest-call';  
         var tag = 'tag' || 'data-from-rest-call';

         // waitUntil is a callback, it triggers when the push is ready.
         event.waitUntil(  
         //here your ready notifications get triggered
         self.registration.showNotification(title, {  
           body: body,  
           icon: icon,  
           tag: tag  
         })  
      );  
    });

Refer google's getting started with web-push-notifications for detailed understanding.