// Specifier should be resolved relative to current file const jsWorker = new Worker("./sibling_worker.js", { type: "module", name: "sibling" }); jsWorker.onerror = _e => { postMessage({ type: "error" }); }; jsWorker.onmessage = e => { postMessage({ type: "msg", text: e }); close(); }; onmessage = function(e) { jsWorker.postMessage(e.data); };