```js
// MyComponent.stories.js

import { INITIAL_VIEWPORTS } from '@storybook/addon-viewport';

export default {
  title: 'MyComponent',
  component: 'my-component',
  parameters: {
    //👇 The viewports object from the Essentials addon
    viewport: {
      //👇 The viewports you want to use
      viewports: INITIAL_VIEWPORTS,
      //👇 Your own default viewport
      defaultViewport: 'iphone6',
    },
  },
};

/*
 *👇 Render functions are a framework specific feature to allow you control on how the component renders.
 * See https://storybook.js.org/docs/7.0/web-components/api/csf
 * to learn how to use render functions.
 */
export const MyStory = {
  parameters: {
    viewport: {
      defaultViewport: 'iphonex',
    },
  },
};
```