MessageEvent: lastEventId property

Note: This feature is available in Web Workers.

The lastEventId read-only property of the MessageEvent interface is a string representing a unique ID for the event.

Value

A string representing the ID.

myWorker.onmessage = (e) => {
  result.textContent = e.data;
  console.log("Message received from worker");
  console.log(e.lastEventId);
};