useFetch

This composable provides a convenient wrapper around useAsyncData and $fetch. It automatically generates a key based on URL and fetch options, provides type hints for request url based on server routes, and infers API response type.

Usage

<script setup lang="ts">
const { data, pending, error, refresh } = await useFetch('/api/modules', {
  pick: ['title']
})
</script>

Using the query option, you can add search parameters to your query. This option is extended from unjs/ofetch and is using unjs/ufo to create the URL. Objects are automatically stringified.

const param1 = ref('value1')
const { data, pending, error, refresh } = await useFetch('/api/modules', {
  query: { param1, param2: 'value2' }
})

The above example results in https://api.nuxt.com/modules?param1=value1&param2=value2.

You can also use interceptors:

const { data, pending, error, refresh } = await useFetch('/api/auth/login', {
  onRequest({ request, options }) {
    // Set the request headers
    options.headers = options.headers || {}
    options.headers.authorization = '...'
  },
  onRequestError({ request, options, error }) {
    // Handle the request errors
  },
  onResponse({ request, response, options }) {
    // Process the response data
    localStorage.setItem('token', response._data.token)
  },
  onResponseError({ request, response, options }) {
    // Handle the response errors
  }
})

Params

• URL: The URL to fetch.
• Options (extends unjs/ofetch options & AsyncDataOptions):
  • method: Request method.
  • query: Adds query search params to URL using ufo
  • params: Alias for query
  • body: Request body - automatically stringified (if an object is passed).
  • headers: Request headers.
  • baseURL: Base URL for the request.
  • timeout: Milliseconds to automatically abort request

• Options (from useAsyncData):
  • key: a unique key to ensure that data fetching can be properly de-duplicated across requests, if not provided, it will be automatically generated based on URL and fetch 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
  • getCachedData: Provide a function which returns cached data. A null or undefined return value will trigger a fetch. By default, this is: key => nuxt.isHydrating ? nuxt.payload.data[key] : nuxt.static.data[key], which only caches data when payloadExtraction is enabled.
  • pick: only pick specified keys in this array from the handler function result
  • watch: watch an array of reactive sources and auto-refresh the fetch result when they change. Fetch options and URL are watched by default. You can completely ignore reactive sources by using watch: false. Together with immediate: false, this allows for a fully-manual useFetch.
  • deep: return data in a deep ref object (it is true by default). It can be set to false to return data in a shallow ref object, which can improve performance if your data does not need to be deeply reactive.
  • dedupe: avoid fetching same key more than once at a time (defaults to cancel). Possible options:
    • cancel - cancels existing requests when a new one is made
    • defer - does not make new requests at all if there is a pending request

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.

Type

function useFetch<DataT, ErrorT>(
  url: string | Request | Ref<string | Request> | () => string | Request,
  options?: UseFetchOptions<DataT>
): Promise<AsyncData<DataT, ErrorT>>

type UseFetchOptions<DataT> = {
  key?: string
  method?: string
  query?: SearchParams
  params?: SearchParams
  body?: RequestInit['body'] | Record<string, any>
  headers?: Record<string, string> | [key: string, value: string][] | Headers
  baseURL?: string
  server?: boolean
  lazy?: boolean
  immediate?: boolean
  getCachedData?: (key: string) => DataT
  deep?: boolean
  dedupe?: 'cancel' | 'defer'
  default?: () => DataT
  transform?: (input: DataT) => DataT | Promise<DataT>
  pick?: string[]
  watch?: WatchSource[] | false
}

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?: 'cancel' | 'defer'
}

type AsyncDataRequestStatus = 'idle' | 'pending' | 'success' | 'error'