beforeRouteUpdate

beforeRouteUpdate is a navigation guard in Vue Router. It is an instance method that can be defined on a component. This hook is called when the route that the component is currently being rendered for has changed, but the component instance itself has not been destroyed. This is particularly useful when a route's parameters or query properties change, but the component remains the same, such as when navigating between different user profiles on a social media application or filtering a list of items.

The primary use case for beforeRouteUpdate is to perform side effects or data fetching based on the updated route information without recreating the component. For example, if a component displays detailed information about a specific item, and the route changes to show a different item's details (e.g., `/items/1` to `/items/2`), beforeRouteUpdate allows the component to fetch the new item's data and update its displayed content.

The hook receives three arguments: to, from, and next. The 'to' argument represents the target route object, 'from' represents the current route object before the navigation, and 'next' is a function that must be called to resolve the hook. Calling next() without any arguments proceeds with the navigation. Calling next(false) aborts the navigation. Calling next('/') or next({ path: '/' }) redirects to a different location.

It's important to note that beforeRouteUpdate should not be confused with beforeRouteEnter. beforeRouteEnter is called before the route is confirmed, and the component instance has not yet been created. Therefore, it cannot access 'this'. In contrast, beforeRouteUpdate is called when the route changes but the component still exists, allowing access to 'this'.