[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<T>(
  type: T,
): UnionType<[Type<"Null", null, null, NullError, null, NullError>, T]>;
```

Defined in: [packages/common/src/Type.ts:3868](https://github.com/evoluhq/evolu/blob/e7144e2bbe9069362b62dec1b64a8aa922b8f1b0/packages/common/src/Type.ts#L3868)

`union(null, T)` [Type](https://evolu.dev/docs/api-reference/common/Type/interfaces/Type).

### Example

```ts
const NullOrString = nullOr(String);
NullOrString.from("hello"); // ok("hello")
NullOrString.from(null); // ok(null)
NullOrString.from(42); // err(...)
```