# useOptionalExternalStore

Source: /tuil/docs/reference/packages/ink/api/use-optional-external-store
Locale: en

function exported by @mwillbanks/tuil-ink.



{/* Generated by tooling/docs/generate-reference.ts. */}

## function [#function]

Public function exported by `@mwillbanks/tuil-ink`.

```ts
export function useOptionalExternalStore<TSnapshot>(
  store: ExternalSnapshotStore<TSnapshot> | undefined,
  emptySnapshot: TSnapshot,
): TSnapshot;
```

## Members [#members]

This declaration has no public members.

## Parameters [#parameters]

| Member          | Type                                            | Required | Description                                                                    | Related types                                                                       |
| --------------- | ----------------------------------------------- | -------- | ------------------------------------------------------------------------------ | ----------------------------------------------------------------------------------- |
| `store`         | `ExternalSnapshotStore<TSnapshot> \| undefined` | Yes      | Supplies the `store` value as `ExternalSnapshotStore<TSnapshot> \| undefined`. | [`ExternalSnapshotStore`](/tuil/docs/reference/packages/ink/api/external-snapshot-store) |
| `emptySnapshot` | `TSnapshot`                                     | Yes      | Supplies the `emptySnapshot` value as `TSnapshot`.                             | —                                                                                   |

## Returns [#returns]

`TSnapshot` — Returns a value that satisfies `TSnapshot`.

Related types: —

## Throws [#throws]

No thrown errors are documented for this declaration.

## Related types [#related-types]

* [`ExternalSnapshotStore`](/tuil/docs/reference/packages/ink/api/external-snapshot-store)

## Source [#source]

[View the secondary source reference](https://github.com/mwillbanks/tuil/blob/main/packages/ink/src/semantics.ts)

## Package [#package]

[@mwillbanks/tuil-ink](/tuil/docs/reference/packages/ink)