The server may set this response header to emit events with the
requested fragment update.
The header value is a relaxed JSON array.
Each element in the array is an object representing an event to be emitted
on the document.
The object property { "type" } defines the event's type. Other properties become properties of the emitted
event object.
Important
HTTP headers may only contain US-ASCII (7-bit) characters.
If you have higher code points in a JSON value, you may
encode those characters using Unicode escape sequences.
Example
Content-Type: text/html
X-Up-Events: [{ type: 'user:created', id: 5012 }, { type: 'signup:completed' }]
...
<html>
...
</html>
Emitting an event on a layer
Instead of emitting an event on the document, the server may also choose to
emit the event on the layer being updated. To do so, add a property
{ layer: 'current' } to the JSON object of an event:
Content-Type: text/html
X-Up-Events: [{ type: 'user:created', name: 'foobar', layer: 'current' }]
...
<html>
...
</html>
