[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) › LowercasedString

```ts
const LowercasedString: lowercased(String);
```

Defined in: [packages/common/src/Type.ts:6490](https://github.com/evoluhq/evolu/blob/ecbac001e0c18bbc45b44715f49ecc3a768c5ec9/packages/common/src/Type.ts#L6490)

Validates lowercased text as TypeScript's `Lowercase<string>`.

Checks the whole string using JavaScript's Unicode lowercase mapping. Empty
strings and uncased characters, such as digits and emoji, are valid. Use
[lowercase](https://evolu.dev/docs/api-reference/common/Type/functions/lowercase) to produce a lowercased value from any string.

### Example

```ts

const text: LowercasedString = "hello world";
assertOk(LowercasedString.fromUnknown(text), text);
assertErr(LowercasedString.fromUnknown("Hello WORLD"));
assertOk(LowercasedString.fromUnknown(""), "");
```