router.beforeEach

router.beforeEach is a method in Vue Router that is used to register a global navigation guard. This method is called before each route navigation and allows you to control access to the routes based on certain conditions.

For example, you can use this method to check if the user is authenticated before allowing access to protected routes. If the user is not authenticated, you can redirect them to the login page.

The syntax for using router.beforeEach is as follows:

router.beforeEach((to, from, next) => {
  // your navigation guard logic here
})

The first parameter is a function that takes three arguments:

- `to`: the route object of the destination route
- `from`: the route object of the current route
- `next`: a callback function that must be called to proceed with the navigation

Inside the function, you can write your navigation guard logic and call the `next` function to proceed with the navigation or to redirect the user to a different route.

Here's an example of using router.beforeEach to check if the user is authenticated before allowing access to protected routes:

router.beforeEach((to, from, next) => {
  const isAuthenticated = checkAuthentication() // your authentication logic here

  if (to.meta.requiresAuth && !isAuthenticated) {
    next({ name: 'login' }) // redirect to login page
  } else {
    next() // proceed with the navigation
  }
})

In this example, we're checking if the destination route requires authentication (`to.meta.requiresAuth`) and if the user is authenticated (`isAuthenticated`). If the user is not authenticated, we're redirecting them to the login page (`next({ name: 'login' })`). If the user is authenticated, we're proceeding with the navigation (`next()`).