```js
// Button.stories.js

export default {
  /* 👇 The title prop is optional.
   * See https://storybook.js.org/docs/html/configure/overview#configure-story-loading
   * to learn how to generate automatic titles
   */
  title: 'Button',
};

/*
 *👇 Render functions are a framework specific feature to allow you control on how the component renders.
 * See https://storybook.js.org/docs/7.0/html/api/csf
 * to learn how to use render functions.
 */
export const Primary = {
  render: () => {
    const btn = document.createElement('button');
    btn.innerText = 'Button';

    btn.className = [
      'storybook-button',
      'storybook-button--medium',
      'storybook-button--primary',
    ].join(' ');

    return btn;
  },
};
```