Nuxt/docs/2.guide/3.going-further/6.nuxt-app.md
2024-01-18 09:59:59 +00:00

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---
title: "NuxtApp"
description: "In Nuxt 3, you can access runtime app context within composables, components and plugins."
links:
- label: Source
icon: i-simple-icons-github
to: https://github.com/nuxt/nuxt/blob/main/packages/nuxt/src/app/nuxt.ts
---
In Nuxt 3, you can access runtime app context within composables, components and plugins.
::read-more{to="https://v2.nuxt.com/docs/internals-glossary/context#the-context" target="_blank"}
In Nuxt 2, this was referred to as **Nuxt context**.
::
## Nuxt App Interface
::read-more{to="/docs/guide/going-further/internals#the-nuxtapp-interface"}
Jump over the `NuxtApp` interface documentation.
::
## Accessing NuxtApp
Within composables, plugins and components you can access `nuxtApp` with [`useNuxtApp()`](/docs/api/composables/use-nuxt-app):
```ts [composables/useMyComposable.ts]
export function useMyComposable () {
const nuxtApp = useNuxtApp()
// access runtime nuxt app instance
}
```
If your composable does not always need `nuxtApp` or you simply want to check if it is present or not, since [`useNuxtApp`](/docs/api/composables/use-nuxt-app) throws an exception, you can use [`tryUseNuxtApp`](/docs/api/composables/use-nuxt-app#tryusenuxtapp) instead.
Plugins also receive `nuxtApp` as the first argument for convenience.
:read-more{to="/docs/guide/directory-structure/plugins"}
## Providing Helpers
You can provide helpers to be usable across all composables and application. This usually happens within a Nuxt plugin.
```ts
const nuxtApp = useNuxtApp()
nuxtApp.provide('hello', (name) => `Hello ${name}!`)
console.log(nuxtApp.$hello('name')) // Prints "Hello name!"
```
::read-more{to="/docs/guide/directory-structure/plugins#providing-helpers"}
It is possible to inject helpers by returning an object with a `provide` key in plugins.
::
::read-more{to="https://v2.nuxt.com/docs/directory-structure/plugins#inject-in-root--context" target="_blank"}
In Nuxt 2 plugins, this was referred to as **inject function**.
::