# Creating Modules

Nuxt provides helper functions (accessed from `@nuxt/kit`) to assist in creating modules that can run on both Nuxt 2 and Nuxt 3.

```js
import { defineNuxtModule } from '@nuxt/kit'

export default defineNuxtModule({
  // The npm package name of your module
  name: '@nuxtjs/sample-module',
  // The key in `nuxt.config` that holds your module options
  configKey: 'sample',
  // Default configuration options for your module
  defaults: {},
  hooks: {},
  setup (options, nuxt) {},
})
```

## Module options

Nuxt will automatically merge the configuration provided to your module (whether passed directly inline or in a configuration section in `nuxt.config`) with the defaults you provide.

```js
export default {
  buildModules: [
    ['@nuxtjs/sample-module', { sampleOption: true }]
  ],
  sample: {
    anotherOption: 42
  }
}
```

## Hooks

For simple modules, you may be able to implement all you need simply with several hooks in this section.

## Setup

If the `hooks` configuration is not enough, you can provide a full setup function, with access to `nuxt`. You will no longer have access to `this` as in the previous Nuxt module specification, but there are dedicated helper functions from `@nuxt/kit` to replace the module container methods from previously.

```js
import { defineNuxtModule, addPlugin } from '@nuxt/kit'

export default defineNuxtModule({
  // ...
  setup (options, nuxt) {
    addPlugin({
      src: path.resolve(__dirname, 'templates/foo.js')
    })
  },
})
```

## Advanced usage

In some cases you may need access to the Nuxt instance in order to define your module, for example, using other Nuxt options:

```js
import { defineNuxtModule } from '@nuxt/kit'

export default defineNuxtModule(nuxt => ({
  // ...
  defaults: {
    root: nuxt.options.rootDir
  },
}))
```

## Module helpers

A number of helpers are also provided for use within this context (with more coming - feature requests welcome) that ensure compatible behavior across Nuxt versions.

* addTemplate
* addErrorLayout
* addLayout
* addPlugin
* addServerMiddleware
* extendBuild
* extendRoutes

Each of these functions provides documentation via IDE hover/autocomplete.