ExtendableMessageEvent: ExtendableMessageEvent() constructor

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since April 2018.

Note: This feature is only available in Service Workers.

The ExtendableMessageEvent() constructor creates a new ExtendableMessageEvent object.

Syntax

js
new ExtendableMessageEvent(type)
new ExtendableMessageEvent(type, options)

Parameters

type

A string with the name of the event. It is case-sensitive and browsers set it to messageerror or message.

options Optional

An object that, in addition of the properties defined in ExtendableEvent(), can have the following properties:

data Optional

The event's data; this can be any data type. It defaults to null.

origin Optional

A string that defines the origin of the corresponding service worker's environment settings object. It defaults to "".

lastEventId Optional

A string that defines the last event ID of the event source. It defaults to "".

source Optional

The Client, ServiceWorker or MessagePort that sent the message. It defaults to null.

ports Optional

An array containing the MessagePort objects connected to the channel sending the message. It defaults to an empty array.

Return value

A new ExtendableMessageEvent object.

Examples

js
const options = {
  data: "hello message",
  source: MessagePortReference,
  ports: MessagePortListReference,
};

const myEME = new ExtendableMessageEvent("message", init);

Specifications

Specification

Service Workers Nightly
# dom-extendablemessageevent-extendablemessageevent

Browser compatibility

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Service Worker API
ExtendableMessageEvent
Constructor
1. ExtendableMessageEvent()
Instance properties
Inheritance
1. ExtendableEvent
2. Event
Related pages for Service Workers API
Guides
1. Using Service Workers