[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) › nullOr

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

Defined in: [packages/common/src/Type.ts:4159](https://github.com/evoluhq/evolu/blob/dd96d79f1dbe9a49fa12ce8e0aa7d3d0177795ca/packages/common/src/Type.ts#L4159)

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

### Example

```ts

const NullableString = nullOr(String);

assertOk(NullableString.fromUnknown(null), null);
```