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ExtendableMessageEvent: source property

The source read-only property of the ExtendableMessageEvent interface returns a reference to the Client object from which the message was sent.

Value

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.

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

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
source 51 17 44 No 38 11.1 51 51 44 41 11.3 5.0

See also

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https://developer.mozilla.org/en-US/docs/Web/API/ExtendableMessageEvent/source