怎么在 push callback 里向 main script 发 message? service-worker.js

console.log("Service Worker Loaded...");
self.addEventListener("push", e => {
  const data = e.data.json();
  console.log("Push Recieved...");
  // post data back to main script
});

我自己挖的坑自己填吧。
service worker 可以得到所有的 clients 也就是所有 register 过这个 service worker 的 script.
```javascript
function sendMessage(message) {
return self.clients.matchAll({
includeUncontrolled: true // https://developer.mozilla.org/en-US/docs/Web/API/Clients/matchAll
}).then(clients => {
// post messages
// only has one client
clients[0].postMessage(message);
});
}
```
在 push event 的 callback function 里调用 sendMessage 就可以吧 remote push message 传回 client.