这是社区的讨论：Add onclose event to MessagePort #1766
当初我提到一个垫片方案，那时是 2020 年，所以当初只有 chrome69+的内核能支持：
const lockReqId = "process-live-" + Date.now() + Math.random();
navigator.locks.request(lockReqId, () => new Promise(() => {}));
postMessage(lockReqId);
worker.addEventListener("message", (me) => {
if (typeof me.data === "string" && me.data.startsWith("process-live-")) {
navigator.locks.request(me.data, () => {
worker.dispatchEvent(new CloseEvent("close"));
});
}
});
现在已经普遍支持
caniuse-locks