storybook/docs/_snippets/storybook-main-advanced-config-example.md

export default {
  viteFinal: async (config, options) => {
    // Update config here
    return config;
  },
  webpackFinal: async (config, options) => {
    // Change webpack config
    return config;
  },
  babel: async (config, options) => {
    return config;
  },
};

// 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 = {
  viteFinal: async (config, options) => {
    // Update config here
    return config;
  },
  webpackFinal: async (config, options) => {
    // Change webpack config
    return config;
  },
  babel: async (config, options) => {
    return config;
  },
};

export default config;