This directory is **optional**, meaning that [`vue-router`](https://router.vuejs.org) won't be included if you only use [app.vue](/guide/directory-structure/app), reducing your application's bundle size.
If you place anything within square brackets, it will be turned into a [dynamic route](https://router.vuejs.org/guide/essentials/dynamic-matching.html) parameter. You can mix and match multiple parameters and even non-dynamic text within a file name or directory.
If you want to access the route using Composition API, there is a global `useRoute` function that will allow you to access the route just like `this.$route` in the Options API.
If you want more control over when the `<NuxtPage>` component is re-rendered (for example, for transitions), you can either pass a string or function via the `pageKey` prop, or you can define a `key` value via `definePageMeta`:
You might want to define metadata for each route in your app. You can do this using the `definePageMeta` macro, which will work both in `<script>` and in `<script setup>`:
If you are using nested routes, the page metadata from all these routes will be merged into a single object. For more on route meta, see the [vue-router docs](https://router.vuejs.org/guide/advanced/meta.html#route-meta-fields).
Much like `defineEmits` or `defineProps` (see [Vue docs](https://vuejs.org/api/sfc-script-setup.html#defineprops-defineemits)), `definePageMeta` is a **compiler macro**. It will be compiled away so you cannot reference it within your component. Instead, the metadata passed to it will be hoisted out of the component. Therefore, the page meta object cannot reference the component (or values defined on the component). However, it can reference imported bindings.
Of course, you are welcome to define metadata for your own use throughout your app. But some metadata defined with `definePageMeta` has a particular purpose:
Nuxt will automatically wrap your page in [the Vue `<KeepAlive>` component](https://vuejs.org/guide/built-ins/keep-alive.html#keepalive) if you set `keepalive: true` in your `definePageMeta`. This might be useful to do, for example, in a parent route which has dynamic child routes, if you want to preserve page state across route changes. You can also set props to be passed to `<KeepAlive>` (see a full list [here](https://vuejs.org/api/built-in-components.html#keepalive)).
You can define the layout used to render the route. This can be either false (to disable any layout), a string or a ref/computed, if you want to make it reactive in some way. [More about layouts](/guide/directory-structure/layouts).
You can define middleware to apply before loading this page. It will be merged with all the other middleware used in any matching parent/child routes. It can be a string, a function (an anonymous/inlined middleware function following [the global before guard pattern](https://router.vuejs.org/guide/advanced/navigation-guards.html#global-before-guards)), or an array of strings/functions. [More about named middleware](/guide/directory-structure/middleware).
You can define transition properties for the `<transition>` components that wraps your pages and layouts, or pass `false` to disable the `<transition>` wrapper for that route. You can see a list of options that can be passed [here](https://vuejs.org/api/built-in-components.html#transition) or read [more about how transitions work](https://vuejs.org/guide/built-ins/transition.html#transition).