plugins

Nuxt automatically reads the files in the app/plugins/ directory and loads them at the creation of the Vue application.

::note All plugins inside are auto-registered, you don't need to add them to your nuxt.config separately. ::

::note You can use .server or .client suffix in the file name to load a plugin only on the server or client side. ::

Registered Plugins#

Only files at the top level of the directory (or index files within any subdirectories) will be auto-registered as plugins.

```bash [Directory structure] -| plugins/ ---| foo.ts // scanned ---| bar/ -----| baz.ts // not scanned -----| foz.vue // not scanned -----| index.ts // currently scanned but deprecated

Only `foo.ts` and `bar/index.ts` would be registered.

To add plugins in subdirectories, you can use the [`app/plugins`](/docs/4.x/api/nuxt-config#plugins-1) option in `nuxt.config.ts`:

```ts twoslash [nuxt.config.ts]
export default defineNuxtConfig({
  plugins: [
    '~/plugins/bar/baz',
    '~/plugins/bar/foz',
  ],
})

Creating Plugins#

The only argument passed to a plugin is nuxtApp.

```ts twoslash [plugins/hello.ts] export default defineNuxtPlugin((nuxtApp) => { // Doing something with nuxtApp })

### Object Syntax Plugins

It is also possible to define a plugin using an object syntax, for more advanced use cases. For example:

```ts twoslash [plugins/hello.ts]
export default defineNuxtPlugin({
  name: 'my-plugin',
  enforce: 'pre', // or 'post'
  async setup (nuxtApp) {
    // this is the equivalent of a normal functional plugin
  },
  hooks: {
    // You can directly register Nuxt app runtime hooks here
    'app:created' () {
      const nuxtApp = useNuxtApp()
      // do something in the hook
    },
  },
  env: {
    // Set this value to `false` if you don't want the plugin to run when rendering server-only or island components.
    islands: true,
  },
})

:video-accordion{title="Watch a video from Alexander Lichter about the Object Syntax for Nuxt plugins" videoId="2aXZyXB1QGQ"}

::note If you are using the object-syntax, the properties are statically analyzed to produce a more optimized build. So you should not define them at runtime. :br For example, setting enforce: import.meta.server ? 'pre' : 'post' would defeat any future optimization Nuxt is able to do for your plugins. Nuxt does statically pre-load any hook listeners when using object-syntax, allowing you to define hooks without needing to worry about order of plugin registration. ::

Registration Order#

You can control the order in which plugins are registered by prefixing with 'alphabetical' numbering to the file names.

```bash [Directory structure] plugins/ | - 01.myPlugin.ts | - 02.myOtherPlugin.ts

In this example, `02.myOtherPlugin.ts` will be able to access anything that was injected by `01.myPlugin.ts`.

This is useful in situations where you have a plugin that depends on another plugin.

::note
In case you're new to 'alphabetical' numbering, remember that filenames are sorted as strings, not as numeric values. For example, `10.myPlugin.ts` would come before `2.myOtherPlugin.ts`. This is why the example prefixes single digit numbers with `0`.
::

## Loading Strategy

### Parallel Plugins

By default, Nuxt loads plugins sequentially. You can define a plugin as `parallel` so Nuxt won't wait until the end of the plugin's execution before loading the next plugin.

```ts twoslash [plugins/my-plugin.ts]
export default defineNuxtPlugin({
  name: 'my-plugin',
  parallel: true,
  async setup (nuxtApp) {
    // the next plugin will be executed immediately
  },
})

Plugins With Dependencies#

If a plugin needs to wait for another plugin before it runs, you can add the plugin's name to the dependsOn array.

``ts twoslash [plugins/depending-on-my-plugin.ts] export default defineNuxtPlugin({ name: 'depends-on-my-plugin', dependsOn: ['my-plugin'], async setup (nuxtApp) { // this plugin will wait for the end ofmy-plugin`'s execution before it runs }, })

## Using Composables

You can use [composables](/docs/4.x/directory-structure/app/composables) as well as [utils](/docs/4.x/directory-structure/app/utils) within Nuxt plugins:

```ts [app/plugins/hello.ts]
export default defineNuxtPlugin((nuxtApp) => {
  const foo = useFoo()
})

However, keep in mind there are some limitations and differences:

::important If a composable depends on another plugin registered later, it might not work. :br

Plugins are called in order sequentially and before everything else. You might use a composable that depends on another plugin which has not been called yet. ::

::important If a composable depends on the Vue.js lifecycle, it won't work. :br

Normally, Vue.js composables are bound to the current component instance while plugins are only bound to nuxtApp instance. ::

Providing Helpers#

If you would like to provide a helper on the NuxtApp instance, return it from the plugin under a provide key.

::code-group ``ts twoslash [plugins/hello.ts] export default defineNuxtPlugin(() => { return { provide: { hello: (msg: string) =>Hello ${msg}!`, }, } })

```ts twoslash [plugins/hello-object-syntax.ts]
export default defineNuxtPlugin({
  name: 'hello',
  setup () {
    return {
      provide: {
        hello: (msg: string) => `Hello ${msg}!`,
      },
    }
  },
})

::

You can then use the helper in your components:

```vue [app/components/Hello.vue]

::important
Note that we highly recommend using [`composables`](/docs/4.x/directory-structure/app/composables) instead of providing helpers to avoid polluting the global namespace and keep your main bundle entry small.
::

::warning
**If your plugin provides a `ref` or `computed`, it will not be unwrapped in a component `<template>`.** :br
This is due to how Vue works with refs that aren't top-level to the template. You can read more about it [in the Vue documentation](https://vuejs.org/guide/essentials/reactivity-fundamentals#caveat-when-unwrapping-in-templates).
::

## Typing Plugins

If you return your helpers from the plugin, they will be typed automatically; you'll find them typed for the return of `useNuxtApp()` and within your templates.

::note
If you need to use a provided helper _within_ another plugin, you can call [`useNuxtApp()`](/docs/4.x/api/composables/use-nuxt-app) to get the typed version. But in general, this should be avoided unless you are certain of the plugins' order.
::

For advanced use-cases, you can declare the type of injected properties like this:

```ts [index.d.ts]
declare module '#app' {
  interface NuxtApp {
    $hello (msg: string): string
  }
}

declare module 'vue' {
  interface ComponentCustomProperties {
    $hello (msg: string): string
  }
}

export {}

Vue Plugins#

If you want to use Vue plugins, like vue-gtag to add Google Analytics tags, you can use a Nuxt plugin to do so.

First, install the Vue plugin dependency:

::code-group{sync="pm"} ```bash [npm] npm install --save-dev vue-gtag-next

```bash [yarn]
yarn add --dev vue-gtag-next

```bash [pnpm] pnpm add -D vue-gtag-next

```bash [bun]
bun add -D vue-gtag-next

```bash [deno] deno add -D npm:vue-gtag-next

::

Then create a plugin file:

```ts [app/plugins/vue-gtag.client.ts]
import VueGtag, { trackRouter } from 'vue-gtag-next'

export default defineNuxtPlugin((nuxtApp) => {
  nuxtApp.vueApp.use(VueGtag, {
    property: {
      id: 'GA_MEASUREMENT_ID',
    },
  })
  trackRouter(useRouter())
})

Vue Directives#

Similarly, you can register a custom Vue directive in a plugin.

ts twoslash [plugins/my-directive.ts] export default defineNuxtPlugin((nuxtApp) => { nuxtApp.vueApp.directive('focus', { mounted (el) { el.focus() }, getSSRProps (binding, vnode) { // you can provide SSR-specific props here return {} }, }) })

::warning If you register a Vue directive, you must register it on both client and server side unless you are only using it when rendering one side. If the directive only makes sense from a client side, you can always move it to ~/plugins/my-directive.client.ts and provide a 'stub' directive for the server in ~/plugins/my-directive.server.ts. ::

:read-more{icon="i-simple-icons-vuedotjs" title="Custom Directives on Vue Docs" to="https://vuejs.org/guide/reusability/custom-directives.html" target="_blank"}