MessageEvent: MessageEvent() constructor

The MessageEvent() constructor creates a new MessageEvent object.

Syntax

new MessageEvent(type)
new MessageEvent(type, options)

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

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

data Optional: The data you want contained in the MessageEvent. This can be of any data type, and will default to null if not specified.
origin Optional: A string representing the origin of the message emitter. This defaults to an empty string ('') if not specified.
lastEventId Optional: A string representing a unique ID for the event. This defaults to an empty string ("") if not specified.
source Optional: A MessageEventSource (which can be a Window, a MessagePort, or a ServiceWorker object) representing the message emitter. This defaults to null if not set.
ports Optional: An array of 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). This defaults to an empty array ([]) if not specified.

const myMessage = new MessageEvent("message", {
  data: "hello",
});

Specification
HTML Standard # the-messageevent-interface:dom-event-constructor

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