Nuxt/docs/content/2.guide/2.directory-structure/1.composables.md
Yaël Guilloux dc47c64f14
docs: use nuxt 3 and website theme (#5479)
Co-authored-by: Daniel Roe <daniel@roe.dev>
Co-authored-by: Sébastien Chopin <seb@nuxtjs.com>
Co-authored-by: Pooya Parsa <pooya@pi0.io>
Co-authored-by: pooya parsa <pyapar@gmail.com>
Co-authored-by: Clément Ollivier <clement.o2p@gmail.com>
2022-10-06 11:15:30 +02:00

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IconDirectory composables Composables Use the composables/ directory to auto-import your Vue composables into your application.

Composables Directory

Nuxt 3 uses the composables/ directory to automatically import your Vue composables into your application using auto-imports!

Under the hood, Nuxt auto generates the file .nuxt/imports.d.ts to declare the types.

Be aware that you have to run nuxi prepare, nuxi dev or nuxi build in order to let Nuxt generates the types. If you create a composable without having the dev server running, typescript will throw an error Cannot find name 'useBar'.

Usage

Method 1: Using named export

export const useFoo = () => {
  return useState('foo', () => 'bar')
}

Method 2: Using default export

// It will be available as useFoo() (camelCase of file name without extension)
export default function () {
  return useState('foo', () => 'bar')
}

Usage: You can now use auto imported composable in .js, .ts and .vue files

<template>
  <div>
    {{ foo }}
  </div>
</template>

<script setup>
const foo = useFoo()
</script>

:LinkExample{link="/examples/auto-imports/composables"}

Examples

Nested Composables

You can use a composable within another composable using auto imports:

export const useFoo = () => {
  const nuxtApp = useNuxtApp()
  const bar = useBar()
}

Access plugin injections

You can access plugin injections from composables:

export const useHello = () => {
  const nuxtApp = useNuxtApp()
  return nuxtApp.$hello
}

How Files Are Scanned

Nuxt only scans files at the top level of the composables/ directory, e.g.:

composables
 | - index.ts // scanned
 | - useFoo.ts // scanned
 | - nested
 | --- utils.ts // not scanned

Only composables/index.ts and composables/useFoo.ts would be searched for imports.

To get auto imports working for nested modules, you could either re-export them (recommended) or configure the scanner to include nested directories:

Example: Re-export the composables you need from the composables/index.ts file:

// Enables auto import for this export
export { utils } from './nested/utils.ts'

Example: Scan nested directories inside the composables/ folder:

export default defineNuxtConfig({
  imports: {
    dirs: [
      // Scan top-level modules
      'composables',
      // ... or scan modules nested one level deep with a specific name and file extension
      'composables/*/index.{ts,js,mjs,mts}',
      // ... or scan all modules within given directory
      'composables/**'
    ]
  }
})