onnotificationclose - Web APIs
the serviceworkerglobalscope.onnotificationclose property is an event handler called whenever the notificationclose event is dispatched on the serviceworkerglobalscope object, that is when a user closes a displayed notification spawned by serviceworkerregistration.shownotification().
... syntax serviceworkerglobalscope.onnotificationclose = function(notificationevent) { ...
... }; serviceworkerglobalscope.addeventlistener('notificationclose', function(notificationevent) { ...
...self.onnotificationclose = function(event) { console.log('on notification close: ', event.notification.tag); }; specifications specification status comment notifications apithe definition of 'onnotificationclick' in that specification.

ServiceWorkerGlobalScope - Web APIs
notificationclose occurs — when a user closes a displayed notification.
... also available via the serviceworkerglobalscope.onnotificationclose property.

Index - Web APIs
3971 onnotificationclose api, experimental, interface, property, reference, serviceworkerglobalscope, onnotificationclose the serviceworkerglobalscope.onnotificationclose property is an event handler called whenever the notificationclose event is dispatched on the serviceworkerglobalscope object, that is when a user closes a displayed notification spawned by serviceworkerregistration.shownotification().