storybook/docs/_snippets/storybook-preset-full-config-object.md

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