ExtendableMessageEvent

The ExtendableMessageEvent interface of the ServiceWorker API represents the event object of a message event fired on a service worker (when a channel message is received on the ServiceWorkerGlobalScope from another context) — extends the lifetime of such events.

This interface inherits from the ExtendableEvent interface.

Constructor

ExtendableMessageEvent.ExtendableMessageEvent()

Creates a new ExtendableMessageEvent object instance.

Properties

Inherits properties from its parent, ExtendableEvent.

ExtendableMessageEvent.data Read only

Returns the event's data. It can be any data type.

ExtendableMessageEvent.origin Read only

Returns the origin of the ServiceWorkerClient that sent the message

ExtendableMessageEvent.lastEventId Read only

Represents, in server-sent events, the last event ID of the event source.

ExtendableMessageEvent.source Read only

Returns a reference to the service worker that sent the message.

ExtendableMessageEvent.ports Read only

Returns the array containing the MessagePort objects representing the ports of the associated message channel.

Methods

Inherits methods from its parent, ExtendableEvent.

Examples

When the following code is used inside a service worker to respond to a push messages by sending the data received via PushMessageData to the main context via a channel message, the event object of onmessage will be a ExtendableMessageEvent.

var port;

self.addEventListener('push', function(e) {
  var obj = e.data.json();

  if(obj.action === 'subscribe' || obj.action === 'unsubscribe') {
    port.postMessage(obj);
  } else if(obj.action === 'init' || obj.action === 'chatMsg') {
    port.postMessage(obj);
  }
});

self.onmessage = function(e) {
  console.log(e);
  port = e.ports[0];
}

Specifications

Specification	Status	Comment
Service Workers The definition of 'ExtendableMessageEvent' in that specification.	Working Draft	Initial definition.

Browser compatibility

[1] Service workers (and Push) have been disabled in the Firefox 45 Extended Support Release (ESR.)

See also

• Using Service Workers
• Service workers basic code example
• Is ServiceWorker ready?
• Channel Messaging