Auto-imports · Nuxt Concepts

Nuxt auto-imports components, composables and Vue.js APIs to use across your application without explicitly importing them.

app.vue

<script setup lang="ts">
const count
 = ref
(1) // ref is auto-imported
</script>

Thanks to its opinionated directory structure, Nuxt can auto-import your components/, composables/ and utils/.

Contrary to a classic global declaration, Nuxt preserves typings, IDEs completions and hints, and only includes what is used in your production code.

In the docs, every function that is not explicitly imported is auto-imported by Nuxt and can be used as-is in your code. You can find a reference for auto-imported components, composables and utilities in the API section.

In the server directory, Nuxt auto-imports exported functions and variables from server/utils/.

You can also auto-import functions exported from custom folders or third-party packages by configuring the imports section of your nuxt.config file.

Built-in Auto-imports

Nuxt auto-imports functions and composables to perform data fetching, get access to the app context and runtime config, manage state or define components and plugins.

<script setup lang="ts">
/* useAsyncData() and $fetch() are auto-imported */
const { data
, refresh
, pending
 } = await useFetch
('/api/hello')
</script>

Vue 3 exposes Reactivity APIs like ref or computed, as well as lifecycle hooks and helpers that are auto-imported by Nuxt.

<script setup lang="ts">
/* ref() and computed() are auto-imported */
const count
 = ref
(1)
const double
 = computed
(() => count
.value
 * 2)
</script>

Vue and Nuxt composables

When you are using the built-in Composition API composables provided by Vue and Nuxt, be aware that many of them rely on being called in the right context.

During a component lifecycle, Vue tracks the temporary instance of the current component (and similarly, Nuxt tracks a temporary instance of nuxtApp) via a global variable, and then unsets it in same tick. This is essential when server rendering, both to avoid cross-request state pollution (leaking a shared reference between two users) and to avoid leakage between different components.

That means that (with very few exceptions) you cannot use them outside a Nuxt plugin, Nuxt route middleware or Vue setup function. On top of that, you must use them synchronously - that is, you cannot use await before calling a composable, except within <script setup> blocks, within the setup function of a component declared with defineNuxtComponent, in defineNuxtPlugin or in defineNuxtRouteMiddleware, where we perform a transform to keep the synchronous context even after the await.

If you get an error message like Nuxt instance is unavailable then it probably means you are calling a Nuxt composable in the wrong place in the Vue or Nuxt lifecycle.

Checkout the asyncContext experimental feature to use Nuxt composables in async functions.

See the full explanation in this GitHub comment.

Example of breaking code:

composables/example.ts

// trying to access runtime config outside a composable
const config
 = useRuntimeConfig
()

export const useMyComposable
 = () => {
  // accessing runtime config here
}

Example of working code:

composables/example.ts

export const useMyComposable
 = () => {
  // Because your composable is called in the right place in the lifecycle,
  // useRuntimeConfig will work here
  const config
 = useRuntimeConfig
()

  // ...
}

Directory-based Auto-imports

Nuxt directly auto-imports files created in defined directories:

components/ for Vue components.
composables/ for Vue composables.
utils/ for helper functions and other utilities.

Read and edit a live example in Docs > Examples > Features > Auto Imports.

Explicit Imports

Nuxt exposes every auto-import with the #imports alias that can be used to make the import explicit if needed:

<script setup lang="ts">
import { ref, computed } from '#imports'

const count = ref(1)
const double = computed(() => count.value * 2)
</script>

Disabling Auto-imports

If you want to disable auto-importing composables and utilities, you can set imports.autoImport to false in the nuxt.config file.

nuxt.config.ts

export default defineNuxtConfig
({
  imports
: {
    autoImport
: false
  }
})

This will disable auto-imports completely but it's still possible to use explicit imports from #imports.

Auto-imported Components

Nuxt also automatically imports components from your ~/components directory, although this is configured separately from auto-importing composables and utility functions.

Read more in Docs > Guide > Directory Structure > Components.

To disable auto-importing components from your own ~/components directory, you can set components.dirs to an empty array (though note that this will not affect components added by modules).

nuxt.config.ts

export default defineNuxtConfig
({
  components
: {
    dirs
: []
  }
})

Auto-import from third-party packages

Nuxt also allows auto-importing from third-party packages.

If you are using the Nuxt module for that package, it is likely that the module has already configured auto-imports for that package.

For example, you could enable the auto-import of the useI18n composable from the vue-i18n package like this:

nuxt.config.ts

export default defineNuxtConfig
({
  imports
: {
    presets
: [
      {
        from
: 'vue-i18n',
        imports
: ['useI18n']
      }
    ]
  }
})

Upgrade Guide

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Vue.js Development

Nuxt uses Vue.js and adds features such as component auto-imports, file-based routing and composables for a SSR-friendly usage.