storybook/docs/_snippets/main-config-env.md

export default {
  // Replace your-framework with the framework you are using (e.g., react-webpack5, vue3-vite)
  framework: '@storybook/your-framework',
  stories: ['../src/**/*.mdx', '../src/**/*.stories.@(js|jsx|mjs|ts|tsx)'],
  /*
   * 👇 The `config` argument contains all the other existing environment variables.
   * Either configured in an `.env` file or configured on the command line.
   */
  env: (config) => ({
    ...config,
    EXAMPLE_VAR: 'An environment variable configured in Storybook',
  }),
};

// Replace your-framework with the framework you are using (e.g., react-webpack5, vue3-vite)
import type { StorybookConfig } from '@storybook/your-framework';

const config: StorybookConfig = {
  framework: '@storybook/your-framework',
  stories: ['../src/**/*.mdx', '../src/**/*.stories.@(js|jsx|mjs|ts|tsx)'],
  /*
   * 👇 The `config` argument contains all the other existing environment variables.
   * Either configured in an `.env` file or configured on the command line.
   */
  env: (config) => ({
    ...config,
    EXAMPLE_VAR: 'An environment variable configured in Storybook',
  }),
};

export default config;