The navigationType read-only property of the NavigationTransition interface returns the type of the ongoing navigation. 
 
An enumerated value representing the type of ongoing navigation.
 The possible values are:
  - 
push: A new location is navigated to, causing a new entry to be pushed onto the history list.  - 
reload: The Navigation.currentEntry is reloaded.  - 
replace: The Navigation.currentEntry is replaced with a new history entry. This new entry will reuse the same key, but be assigned a different id.  - 
traverse: The browser navigates from one existing history entry to another existing history entry.  
 
console.log(navigation.transition.navigationType);