Allow mocking in global 'preview' config

[CHE1RON]

Is your feature request related to a problem? Please describe.

I would like to be able to mock modules globally, moving the beforeEach call to Preview. This way, I could apply an option passed via globals to mockReturnValue.

Describe the solution you'd like

I want to include a global OS emulation dropdown like this:

// src/path/to/MyStory.stories.tsx
export const Playground: Story = {
  beforeEach({ globals }) {
    // @ts-expect-error
    isApple.mockReturnValue(globals.os === 'mac');
  },
};

// .storybook/preview.ts
import type { Preview } from '@storybook/react';

// Problem: subpath import for '#utils' not possible here!
// import { isApple } from '#utils' 

const preview: Preview = {
  // ..

  globalTypes: {
    os: {
      name: 'OS family',
      description: 'Applies OS family',
      defaultValue: 'win',
      toolbar: {
        icon: 'memory',
        items: [
          { title: 'Microsoft', value: 'win' },
          { title: 'Apple', value: 'mac' },
        ],
      },
    },
  },

  // ..

  parameters: {
    beforeEach({ globals }) {
      // Problem: See above!
      // isApple.mockReturnValue(globals.os === 'mac');
    },
  }
}

export default preview

Describe alternatives you've considered

Putting beforeEach into every story where OS differences occur

Are you able to assist to bring the feature to reality?

no

Additional context

Especially keybindings differ between OS families, so I need an elegant way to implement a switch/dropdown.