let channel; let port; onmessage = (e) => { if (e.data.port) { port = e.data.port; port.onmessage = (event) => channel.send(event.data.message); } if (e.data.channel) { channel = e.data.channel; channel.onopen = () => port.postMessage("opened"); channel.onerror = () => port.postMessage("errored"); channel.onclose = () => port.postMessage("closed"); channel.onmessage = (event) => port.postMessage(event.data); } };