ExtendableMessageEvent: lastEventId property
Note: This feature is only available in Service Workers.
The lastEventID
read-only property of the
ExtendableMessageEvent
interface represents, in server-sent events, the last event ID of the event source. This is an empty string.
Value
A string.
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.lastEventId);
port = e.ports[0];
};
Specifications
Specification |
---|
Service Workers # extendablemessage-event-lasteventid |
Browser compatibility
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