The dispose event of the NavigationHistoryEntry interface is fired when the entry is no longer part of the history entry list.
Disposal occurs when:
Use the event name in methods like addEventListener(), or set an event handler property.
addEventListener("dispose", (event) => { })
ondispose = (event) => { }A generic Event.
navigation.addEventListener("currententrychange", () => {
navigation.currentEntry.addEventListener("dispose", disposeHandler);
});