是否可以从新员工中检测到现有服务人员的存在？

如何解决是否可以从新员工中检测到现有服务人员的存在？

我有一个复杂的服务人员。安装时，其初始设置行为需要更改，具体取决于是否已经有其他服务工作人员作为原始服务器。

是否有可能最好在install事件期间从服务人员内部检测到另一个服务人员是否已处于活动状态？

在页面上下文中，看来我可以使用navigator.serviceWorker.getRegistrations()，但是navigator.serviceWorker在服务工作者内部是未定义的。

解决方法

假设您在两次部署之间不更改服务工作者的URL或范围，则应该能够从self.registration获取该信息。

self.addEventListener('install',(event) => {
  const {installing,waiting,active} = self.registration;

  // Since we're in the install handler,`installing` should
  // be set to the SW whose global state is `self`.

  // `waiting` is likely to be `null`,unless there happened to be a SW
  // that was waiting to activate at the point this SW started install.

  // `active` is what you're most interested in. If it's null,then there
  // isn't already an active SW with the same registration info.
  // If it's set to a SW,then you know that there is one.
});