ExtendableMessageEvent: source property
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 inService Workers.
Thesource read-only property of theExtendableMessageEvent interface returns a reference to theClient object from which the message was sent.
Value
AClient,ServiceWorker orMessagePortobject.
Examples
When the following code is used inside a service worker to respond to a push messagesby sending the data received viaPushMessageData to the main context viaachannel message, the eventobject ofonmessage will be anExtendableMessageEvent.
js
let port;self.addEventListener("push", (e) => { const 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 = (e) => { console.log(e.source); port = e.ports[0];};Specifications
| Specification |
|---|
| Service Workers Nightly # extendablemessage-event-source |