Worker: messageerror event

{{APIRef("Web Workers API")}} {{AvailableInWorkers("window_and_worker_except_service")}} 

The messageerror event is fired on a {{domxref('Worker')}}  object when it receives a message that can’t be deserialized.

This event is not cancellable and does not bubble.

Syntax

Use the event name in methods like {{domxref("EventTarget.addEventListener", "addEventListener()")}} , or set an event handler property.

addEventListener("messageerror", (event) => {});

onmessageerror = (event) => {};

Event type

A {{domxref("MessageEvent")}} . Inherits from {{domxref("Event")}} .

{{InheritanceDiagram("MessageEvent")}} 

Event properties

This interface also inherits properties from its parent, {{domxref("Event")}} .

• {{domxref("MessageEvent.data")}}  {{ReadOnlyInline}} 
  • : The data sent by the message emitter.
• {{domxref("MessageEvent.origin")}}  {{ReadOnlyInline}} 
  • : A string representing the origin of the message emitter.
• {{domxref("MessageEvent.lastEventId")}}  {{ReadOnlyInline}} 
  • : A string representing a unique ID for the event.
• {{domxref("MessageEvent.source")}}  {{ReadOnlyInline}} 
  • : A MessageEventSource (which can be a {{glossary("WindowProxy")}} , {{domxref("MessagePort")}} , or {{domxref("ServiceWorker")}}  object) representing the message emitter.
• {{domxref("MessageEvent.ports")}}  {{ReadOnlyInline}} 
  • : An array of {{domxref("MessagePort")}}  objects representing the ports associated with the channel the message is being sent through (where appropriate, e.g. in channel messaging or when sending a message to a shared worker).

Examples

Create a worker, and listen for message and messageerror events using addEventListener():

// main.js

const worker = new Worker("static/scripts/worker.js");

worker.addEventListener("message", (event) => {
  console.error(`Received message from worker: ${event}`);
});

worker.addEventListener("messageerror", (event) => {
  console.error(`Error receiving message from worker: ${event}`);
});

The same, but using the onmessageerror event handler property:

// main.js

const worker = new Worker("static/scripts/worker.js");

worker.onmessage = (event) => {
  console.error(`Received message from worker: ${event}`);
};

worker.onmessageerror = (event) => {
  console.error(`Error receiving message from worker: ${event}`);
};

Specifications

{{Specifications}} 

Browser compatibility

{{Compat}} 

See also

• Worker.postMessage()
• Related events: message