```js
// .storybook/main.js|ts

const preprocess = require('svelte-preprocess');

module.exports = {
  stories: ['../stories/**/*.stories.mdx', '../stories/**/*.stories.@(js|jsx|ts|tsx)'],
  addons: ['@storybook/addon-links', '@storybook/addon-essentials'],
  core: {
    builder: '@storybook/builder-vite',
  },
  async viteFinal(config, { configType }) {
    // Customize the Vite config here
    return config;
  },
  framework:{
    name: '@storybook/svelte-webpack5', 
    options: {
      preprocess: preprocess({
        typescript: true,
        postcss: true,
        sourceMap: true,
      }),
    },
  },
};
```