# addRouteMiddleware

> addRouteMiddleware() is a helper function to dynamically add middleware in your application.

<note>

Route middleware are navigation guards stored in the [`app/middleware/`](/docs/4.x/directory-structure/app/middleware) directory of your Nuxt application (unless [set otherwise](/docs/4.x/api/nuxt-config#middleware)).

</note>

## Type

```ts
function addRouteMiddleware (name: string, middleware: RouteMiddleware, options?: AddRouteMiddlewareOptions): void
function addRouteMiddleware (middleware: RouteMiddleware): void

interface AddRouteMiddlewareOptions {
  global?: boolean
}
```

## Parameters

### `name`

- **Type:** `string` | `RouteMiddleware`

Can be either a string or a function of type `RouteMiddleware`. Function takes the next route `to` as the first argument and the current route `from` as the second argument, both of which are Vue route objects.

Learn more about available properties of [route objects](/docs/4.x/api/composables/use-route).

### `middleware`

- **Type:** `RouteMiddleware`

The second argument is a function of type `RouteMiddleware`. Same as above, it provides `to` and `from` route objects. It becomes optional if the first argument in `addRouteMiddleware()` is already passed as a function.

### `options`

- **Type:** `AddRouteMiddlewareOptions`

An optional `options` argument lets you set the value of `global` to `true` to indicate whether the router middleware is global or not (set to `false` by default).

## Examples

### Named Route Middleware

Named route middleware is defined by providing a string as the first argument and a function as the second:

```ts [app/plugins/my-plugin.ts]
export default defineNuxtPlugin(() => {
  addRouteMiddleware('named-middleware', () => {
    console.log('named middleware added in Nuxt plugin')
  })
})
```

When defined in a plugin, it overrides any existing middleware of the same name located in the `app/middleware/` directory.

### Global Route Middleware

Global route middleware can be defined in two ways:

- Pass a function directly as the first argument without a name. It will automatically be treated as global middleware and applied on every route change.```ts [app/plugins/my-plugin.ts]
export default defineNuxtPlugin(() => {
  addRouteMiddleware((to, from) => {
    console.log('anonymous global middleware that runs on every route change')
  })
})
```
- Set an optional, third argument `{ global: true }` to indicate whether the route middleware is global.```ts [app/plugins/my-plugin.ts]
export default defineNuxtPlugin(() => {
  addRouteMiddleware('global-middleware', (to, from) => {
    console.log('global middleware that runs on every route change')
  },
  { global: true },
  )
})
```