当尝试使用广播频道在主脚本和工作者之间进行通信时,我遇到了一些问题。我在主脚本中有以下代码:
const channel = new BroadcastChannel('my_bus');
const worker = new Worker('worker.js');
const secondWorker = new Worker('second-worker.js');
channel.postMessage('1000');
以及两个工人中的类似代码:
const bc = new BroadcastChannel('my_bus');
bc.onmessage = () => {
console.log('worker get length');
}
问题是当主脚本发出的消息,工作者尚未加载时,所以他们跳过了消息。我很确定,因为如果我做这样的事情,它可以正常工作:
setTimeout(() => {
channel.postMessage('1000');
}, 100)
有没有办法在工作脚本加载后触发回调?
根据最后的评论,我会写下我的建议作为答案:
您可以让工作人员在加载时发出消息,并在主脚本上侦听该消息。这通常是我们对网络工作者做的事情:他们向主线程发出一条消息,说“我准备接收东西”。
可能的实现可能是:
// assumes the first `message` from workers is always the "loaded" ones
const loaded = w =>
new Promise(r => w.addEventListener("message", r, { once: true }));
// Code runs inside async function, so we can use `await`
async function main() {
const channel = new BroadcastChannel("my_bus");
const worker = new Worker("worker.js");
const secondWorker = new Worker("second-worker.js");
await Promise.all([
loaded(worker),
loaded(secondWorker)
]);
// this will be post only once all the workers have been loaded
channel.postMessage("1000");
}
// call the main function
main();
工人的代码如下:
const bc = new BroadcastChannel("my_bus");
bc.onmessage = () => {
console.log("worker get length");
};
postMessage("loaded");