Web Worker

function createWorker(fn) {
  const blob = new Blob([`(${fn.toString()})()`], { type: "application/javascript" });
  const worker = new Worker(URL.createObjectURL(blob));
  return worker;
}

const worker = createWorker(() => {
  self.onmessage = e => {
    const result = e.data.reduce((s, n) => s + n, 0);
    self.postMessage(result);
  };
});
worker.postMessage([1, 2, 3, 4, 5]);
worker.onmessage = e => console.log(e.data);