[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) › Null

```ts
const Null: base("Null", (value) =>
  value === null ? ok(value) : err<NullError>({ type: "Null", value }),
);
```

Defined in: [packages/common/src/Type.ts:807](https://github.com/evoluhq/evolu/blob/e7144e2bbe9069362b62dec1b64a8aa922b8f1b0/packages/common/src/Type.ts#L807)