The NavigationCurrentEntryChangeEvent() constructor creates a new NavigationCurrentEntryChangeEvent object.

type

A string representing the type of event. In the case of NavigationCurrentEntryChangeEvent this is always event.

init

An object containing the following properties:

destination

A NavigationHistoryEntry object representing the location being navigated to.

navigationType

The type of the navigation that resulted in the change. Possible values — push, reload, replace, and traverse.

A developer would not use this constructor manually. A new NavigationCurrentEntryChangeEvent object is constructed when a handler is invoked as a result of the currententrychange event firing.

navigation.addEventListener("currententrychange", (event) => {
  console.log(event.navigationType);
});

• Modern client-side routing: the Navigation API
• Navigation API explainer
• Domenic Denicola's Navigation API live demo