# Extending Components

All `cva` components provide an optional `class` **or** `className` prop, which can be used to pass additional classes to the component.

```ts
// components/button.ts
import { cva } from "class-variance-authority";

const button = cva(/* … */);

button({ class: "m-4" });
// => "…buttonClasses m-4"

button({ className: "m-4" });
// => "…buttonClasses m-4"
```
