ServiceWorker.state

实验性: 这是一项实验性技术
在将其用于生产之前，请仔细检查浏览器兼容性表格。

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。

js

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

Specification
Service Workers
# service-worker-state

浏览器兼容性

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