onBeforeRouteLeave 
ts
function onBeforeRouteLeave(hook): RouteHookRemoveRegisters a hook that is called before a route is left. Must be called from setup. This is useful for performing actions or cleanups before navigating away from a route component.
Parameters 
| Parameter | Type | 
|---|---|
hook | BeforeRouteHook | 
Returns 
A function that removes the added hook.