# createUseAsyncData
> A factory function to create a custom useAsyncData composable with pre-defined default options.
`createUseAsyncData` creates a custom [`useAsyncData`](/docs/4.x/api/composables/use-async-data) composable with pre-defined options. The resulting composable is fully typed and works exactly like `useAsyncData`, but with your defaults baked in.
`createUseAsyncData` is a compiler macro. It must be used as an **exported** declaration in the `composables/` directory (or any directory scanned by the Nuxt compiler). Nuxt automatically injects de-duplication keys at build time.
## Usage
```ts [app/composables/useCachedData.ts]
export const useCachedData = createUseAsyncData({
getCachedData (key, nuxtApp) {
return nuxtApp.payload.data[key] ?? nuxtApp.static.data[key]
},
})
```
```vue [app/pages/index.vue]
```
The resulting composable has the same signature and return type as [`useAsyncData`](/docs/4.x/api/composables/use-async-data), with all options available for the caller to use or override.
## Type
```ts [Signature]
function createUseAsyncData (
options?: Partial,
): typeof useAsyncData
function createUseAsyncData (
options: (callerOptions: AsyncDataOptions) => Partial,
): typeof useAsyncData
```
## Options
`createUseAsyncData` accepts all the same options as [`useAsyncData`](/docs/4.x/api/composables/use-async-data#params), including `server`, `lazy`, `immediate`, `default`, `transform`, `pick`, `getCachedData`, `deep`, `dedupe`, `timeout`, and `watch`.
See the full list of options in the [`useAsyncData` documentation](/docs/4.x/api/composables/use-async-data#params).
## Default vs Override Mode
### Default Mode (plain object)
When you pass a plain object, the factory options act as **defaults**. Callers can override any option:
```ts [app/composables/useLazyData.ts]
export const useLazyData = createUseAsyncData({
lazy: true,
server: false,
})
```
```ts
// Uses the defaults (lazy: true, server: false)
const { data } = await useLazyData('key', () => fetchSomeData())
// Caller overrides server to true
const { data } = await useLazyData('key', () => fetchSomeData(), { server: true })
```
### Override Mode (function)
When you pass a function, the factory options **override** the caller's options. The function receives the caller's options as its argument:
```ts [app/composables/useStrictData.ts]
// deep is always enforced as false
export const useStrictData = createUseAsyncData(callerOptions => ({
deep: false,
}))
```
---
- [Source](https://github.com/nuxt/nuxt/blob/main/packages/nuxt/src/app/composables/asyncData.ts)