Nuxt/docs/2.guide/2.directory-structure/1.plugins.md
2024-05-13 15:39:52 +01:00

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---
title: "plugins"
description: "Nuxt has a plugins system to use Vue plugins and more at the creation of your Vue application."
head.title: "plugins/"
navigation.icon: i-ph-folder-duotone
---
Nuxt automatically reads the files in the `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 [`plugins`](/docs/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`](/docs/api/composables/use-nuxt-app).
```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
}
})
```
::tip{icon="i-ph-video-duotone" to="https://www.youtube.com/watch?v=2aXZyXB1QGQ" target="_blank"}
Watch a video from Alexander Lichter about the Object Syntax for Nuxt plugins.
::
::note
If you are using the object-syntax, the properties may be statically analyzed in future 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.
::
## 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 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 of `my-plugin`'s execution before it runs
}
})
```
## Using Composables
You can use [composables](/docs/guide/directory-structure/composables) as well as [utils](/docs/guide/directory-structure/utils) within Nuxt plugins:
```ts [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`](/docs/api/composables/use-nuxt-app) instance.
::
## Providing Helpers
If you would like to provide a helper on the [`NuxtApp`](/docs/api/composables/use-nuxt-app) 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 [components/Hello.vue]
<script setup lang="ts">
// alternatively, you can also use it here
const { $hello } = useNuxtApp()
</script>
<template>
<div>
{{ $hello('world') }}
</div>
</template>
```
::important
Note that we highly recommend using [`composables`](/docs/guide/directory-structure/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.html#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/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 {}
```
::note
If you are using WebStorm, you may need to augment `@vue/runtime-core` until [this issue](https://youtrack.jetbrains.com/issue/WEB-59818/VUE-TypeScript-WS-PS-does-not-correctly-display-type-of-globally-injected-properties) is resolved.
::
## Vue Plugins
If you want to use Vue plugins, like [vue-gtag](https://github.com/MatteoGabriele/vue-gtag) to add Google Analytics tags, you can use a Nuxt plugin to do so.
First, install the Vue plugin dependency:
::code-group
```bash [yarn]
yarn add --dev vue-gtag-next
```
```bash [npm]
npm install --save-dev vue-gtag-next
```
```bash [pnpm]
pnpm add -D vue-gtag-next
```
```bash [bun]
bun add -D vue-gtag-next
```
::
Then create a plugin file:
```ts [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"}