Nuxt/docs/6.bridge/4.plugins-and-middleware.md

title	description
Plugins and Middleware	Learn how to migrate from Nuxt 2 to Nuxt Bridge new plugins and middleware.

New Plugins Format

You can now migrate to the Nuxt 3 plugins API, which is slightly different in format from Nuxt 2.

Plugins now take only one argument (nuxtApp). You can find out more in the docs.

export default defineNuxtPlugin(nuxtApp => {
  nuxtApp.provide('injected', () => 'my injected function')
  // now available on `nuxtApp.$injected`
})

::note If you want to use the new Nuxt composables (such as useNuxtApp or useRuntimeConfig) within your plugins, you will need to use the defineNuxtPlugin helper for those plugins. ::

::warning Although a compatibility interface is provided via nuxtApp.vueApp you should avoid registering plugins, directives, mixins or components this way without adding your own logic to ensure they are not installed more than once, or this may cause a memory leak. ::

New Middleware Format

You can now migrate to the Nuxt 3 middleware API, which is slightly different in format from Nuxt 2.

Middleware now take only two argument (to, from). You can find out more in the docs.

export default defineNuxtRouteMiddleware((to) => {
  if (to.path !== '/') {
    return navigateTo('/')
  }
})

::important Use of defineNuxtRouteMiddleware is not supported outside of the middleware directory. ::

definePageMeta

You can also use definePageMeta in Nuxt Bridge.

You can be enabled with the macros.pageMeta option in your configuration file

import { defineNuxtConfig } from '@nuxt/bridge'

export default defineNuxtConfig({
  bridge: {
    macros: {
      pageMeta: true
    }
  }
})

::note But only for middleware and layout. ::