ExtendableMessageEvent.ports

The ports read-only property of the ExtendableMessageEvent interface returns the array containing the MessagePort objects representing the ports of the associated message channel (the channel the message is being sent through.)

Syntax

var myPorts = extendableMessageEvent.ports;

Value

An array of MessagePort objects.

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) {
  port = e.ports[0];
}

Specifications

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

Browser compatibility

DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
ports
Experimental
Chrome ? Edge ? Firefox Full support 45
Notes
Full support 45
Notes
Notes Extended Support Releases (ESR) before Firefox 78 ESR do not support service workers and the Push API.
IE No support NoOpera ? Safari No support NoWebView Android No support NoChrome Android ? Firefox Android Full support 45Opera Android ? Safari iOS No support NoSamsung Internet Android ?

Legend

Full support
Full support
No support
No support
Compatibility unknown
Compatibility unknown
Experimental. Expect behavior to change in the future.
Experimental. Expect behavior to change in the future.
See implementation notes.
See implementation notes.

See also