[API reference](https://evolu.dev/docs/api-reference) › [@evolu/common](https://evolu.dev/docs/api-reference/common) › [Type](https://evolu.dev/docs/api-reference/common/Type) › nullishOr

```ts
function nullishOr<ValueType>(
  type: ValidateUnionTypeMember<ValueType>,
): UnionType<readonly [ValueType, LiteralType<null>, LiteralType<undefined>]>;
```

Defined in: [packages/common/src/Type.ts:4179](https://github.com/evoluhq/evolu/blob/dd96d79f1dbe9a49fa12ce8e0aa7d3d0177795ca/packages/common/src/Type.ts#L4179)

Union [Type](https://evolu.dev/docs/api-reference/common/Type/interfaces/Type) containing the supplied Type, `null`, and `undefined`.

### Example

```ts

const NullishString = nullishOr(String);

assertOk(NullishString.fromUnknown(undefined), undefined);
assertOk(NullishString.fromUnknown(null), null);
```