```ts
// MyComponent.stories.ts

import { Story, Meta } from '@storybook/angular/types-6-0';
import MyComponent from './mycomponent.component';

export default {
  component: MyComponent,
  title: 'A story using environment variables inside a .env file',
} as Meta;

const Template: Story<MyComponent> = (args: MyComponent) => ({
  component: MyComponent,
  props: args
});

export const Default = Template.bind({});
Default.args = {
  propertyA: process.env.STORYBOOK_DATA_KEY
};
```