[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
type LowercasedString = Lowercase<string>;
```

Defined in: [packages/common/src/Type.ts:6490](https://github.com/evoluhq/evolu/blob/dd96d79f1dbe9a49fa12ce8e0aa7d3d0177795ca/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(""), "");
```