Nuxt/docs/content/3.api/1.composables/use-async-data.md

useAsyncData

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

Type

function useAsyncData(
  handler: (nuxtApp?: NuxtApp) => Promise<DataT>,
  options?: AsyncDataOptions<DataT>
): AsyncData<DataT>
function useAsyncData(
  key: string,
  handler: (nuxtApp?: NuxtApp) => Promise<DataT>,
  options?: AsyncDataOptions<DataT>
): Promise<AsyncData<DataT>>

type AsyncDataOptions<DataT> = {
  server?: boolean
  lazy?: boolean
  default?: () => DataT | Ref<DataT> | null
  transform?: (input: DataT) => DataT
  pick?: string[]
  watch?: WatchSource[]
  initialCache?: boolean
}

interface RefreshOptions {
  _initial?: boolean
}

type AsyncData<DataT, ErrorT> = {
  data: Ref<DataT | null>
  pending: Ref<boolean>
  refresh: (opts?: RefreshOptions) => Promise<void>
  error: Ref<ErrorT | null>
}

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 returns a value
• options:
  • lazy: whether to resolve the async function after loading the route, instead of blocking client-side navigation (defaults to false)
  • default: a factory function to set the default value of the data, before the async function resolves - particularly useful with the lazy: true option
  • server: whether to fetch the data on the server (defaults to true)
  • 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
  • initialCache: When set to false, will skip payload cache for initial fetch. (defaults to true)

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.

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: a function that can be used to refresh the data returned by the handler function
• error: an error object if the data fetching failed

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

::alert{type=warning} 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>. ::

Example

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

::ReadMore{link="/guide/features/data-fetching"} ::