useAsyncData

Within your pages, components, and plugins you can use useAsyncData to get access to data that resolves asynchronously.

useAsyncData is a composable meant to be called directly in a setup function, plugin, or route middleware. It returns reactive composables and handles adding responses to the Nuxt payload so they can be passed from server to client without re-fetching the data on client side when the page hydrates.

Usage

pages/index.vue

<script setup>const { data, pending, error, refresh } = await useAsyncData(  'mountains',  () => $fetch('https://api.nuxtjs.dev/mountains'))</script>

Watch Params

The built-in watch option allows automatically rerunning the fetcher function when any changes are detected.

pages/index.vue

<script setup>const page = ref(1)const { data: posts } = await useAsyncData(  'posts',  () => $fetch('https://fakeApi.com/posts', {    params: {      page: page.value    }  }), {    watch: [page]  })</script>

useAsyncData is a reserved function name transformed by the compiler, so you should not name your own function useAsyncData .

Read more in Docs > Getting Started > Data Fetching #useasyncdata.

Params

key: a unique key to ensure that data fetching can be properly de-duplicated across requests. If you do not provide a key, then a key that is unique to the file name and line number of the instance of useAsyncData will be generated for you.
handler: an asynchronous function that must return a truthy value (for example, it should not be undefined or null) or the request may be duplicated on the client side
options:
- server: whether to fetch the data on the server (defaults to true)
- lazy: whether to resolve the async function after loading the route, instead of blocking client-side navigation (defaults to false)
- immediate: when set to false, will prevent the request from firing immediately. (defaults to true)
- default: a factory function to set the default value of the data, before the async function resolves - useful with the lazy: true or immediate: false option
- transform: a function that can be used to alter handler function result after resolving
- pick: only pick specified keys in this array from the handler function result
- watch: watch reactive sources to auto-refresh

Under the hood, lazy: false uses <Suspense> to block the loading of the route before the data has been fetched. Consider using lazy: true and implementing a loading state instead for a snappier user experience.

You can use useLazyAsyncData to have the same behavior as lazy: true with useAsyncData.

Return Values

data: the result of the asynchronous function that is passed in.
pending: a boolean indicating whether the data is still being fetched.
refresh/execute: a function that can be used to refresh the data returned by the handler function.
error: an error object if the data fetching failed.
status: a string indicating the status of the data request ("idle", "pending", "success", "error").

By default, Nuxt waits until a refresh is finished before it can be executed again.

If you have not fetched data on the server (for example, with server: false), then the data will not be fetched until hydration completes. This means even if you await useAsyncData on the client side, data will remain null within <script setup>.

Type

Signature

function useAsyncData<DataT, DataE>(  handler: (nuxtApp?: NuxtApp) => Promise<DataT>,  options?: AsyncDataOptions<DataT>): AsyncData<DataT, DataE>function useAsyncData<DataT, DataE>(  key: string,  handler: (nuxtApp?: NuxtApp) => Promise<DataT>,  options?: AsyncDataOptions<DataT>): Promise<AsyncData<DataT, DataE>type AsyncDataOptions<DataT> = {  server?: boolean  lazy?: boolean  immediate?: boolean  default?: () => DataT | Ref<DataT> | null  transform?: (input: DataT) => DataT  pick?: string[]  watch?: WatchSource[]}type AsyncData<DataT, ErrorT> = {  data: Ref<DataT | null>  pending: Ref<boolean>  refresh: (opts?: AsyncDataExecuteOptions) => Promise<void>  execute: (opts?: AsyncDataExecuteOptions) => Promise<void>  error: Ref<ErrorT | null>  status: Ref<AsyncDataRequestStatus>};interface AsyncDataExecuteOptions {  dedupe?: boolean}type AsyncDataRequestStatus = 'idle' | 'pending' | 'success' | 'error'

Read more in Docs > Getting Started > Data Fetching.

useAppConfig

Access the reactive app config defined in the project.

useCookie

useCookie is an SSR-friendly composable to read and write cookies.