v-slot navigate function - return optional Promise

[aeharding]

What problem does this feature solve?

I am trying to create a button within a router-link that shows a loading indicator when clicked (but still allows opening in a new tab, which should not show a loading indicator).

It would be nice if navigate($event) in the v-slot API could return a promise when it performs a .push/replace() so that I could stop the loading animation when the route fails to load, or succeeds, just like router.push/replace(to) does.

Right now the only way to do this in my app is to implement a programmatic push or replace call, which does not allow opening in a new tab.

Thank you so much!

What does the proposed API look like?

navigate(e) returns a Promise (the result of .push or .replace) if either of those functions are called within navigate(e). If neither is called, return nothing.

[posva]

It's a bit more complex than just returning the result of push/replace as we also need to support environments with No Promise. https://github.com/vuejs/vue-router/blob/dev/src/components/link.js#L71-L77