ServiceWorker.state

Experimental: 这是一个实验中的功能
此功能某些浏览器尚在开发中，请参考浏览器兼容性表格以得到在不同浏览器中适合使用的前缀。由于该功能对应的标准文档可能被重新修订，所以在未来版本的浏览器中该功能的语法和行为可能随之改变。

ServiceWorker接口的这个只读的state属性返回一个代表service worker当前状态的字符串。值可以是以下这些：installing, installed, activating, activated, 或者是redundant.

语法

someURL = ServiceWorker.state

值

一个 ServiceWorkerState (en-US) 的定义值 (see the spec.)

示例

这块代码出自 service worker registration-events sample (live demo). 代码监听了任何ServiceWorker.state中的改变，并返回它的值.

var serviceWorker;
if (registration.installing) {
  serviceWorker = registration.installing;
  document.querySelector('#kind').textContent = 'installing';
} else if (registration.waiting) {
  serviceWorker = registration.waiting;
  document.querySelector('#kind').textContent = 'waiting';
} else if (registration.active) {
  serviceWorker = registration.active;
  document.querySelector('#kind').textContent = 'active';
}

if (serviceWorker) {
  logState(serviceWorker.state);
  serviceWorker.addEventListener('statechange', function(e) {
  logState(e.target.state);
  });
}

规范

规范	状态	附注
Service Workers state	Working Draft	Initial definition

We're converting our compatibility data into a machine-readable JSON format. This compatibility table still uses the old format, because we haven't yet converted the data it contains. Find out how you can help! (en-US)

Desktop
Mobile

Feature	Chrome	Firefox (Gecko)	Internet Explorer	Opera	Safari (WebKit)
Basic support	40.0	44.0 (44.0)^[1]	未实现	24	未实现

Feature	Android	Android Webview	Firefox Mobile (Gecko)	Firefox OS	IE Mobile	Opera Mobile	Safari Mobile	Chrome for Android
Basic support	未实现	未实现	44.0 (44.0)	(Yes)	未实现	?	未实现	40.0

[1] Service workers (and Push) have been disabled in the Firefox 45 and 52 Extended Support Releases (ESR.)