[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) › lowercase

```ts
function lowercase<S>(value: S): Lowercase<S>;
```

Defined in: [packages/common/src/Type.ts:6513](https://github.com/evoluhq/evolu/blob/dd96d79f1dbe9a49fa12ce8e0aa7d3d0177795ca/packages/common/src/Type.ts#L6513)

Lowercases the whole string and returns a [LowercasedString](https://evolu.dev/docs/api-reference/common/Type/variables/LowercasedString).

Leaves an empty string unchanged. Uses JavaScript's default Unicode casing
without locale-specific rules. Changing case can change the length, so input
brands are not retained.

### Example

```ts

const text = lowercase("Hello WORLD");
assertEqual(text, "hello world");
assertType<typeof text, "hello world">();
assertEqual(lowercase(text), text);
```