Question: Storybook with rollup.js and TypeScript does not work

[digital-h]

Apperantly I have an issue running Storybook (version 6) with TypeScript using rollup.js through yarn build-storybook.

As long as I only include stories which relate to plain javascript-modules, everything runs fine. But as soon as I add a story, which releates to a typescript-module, the complete storybook is broken (means the skeleton is there, but waiting for content). Unfortunately without any error-message, that might help me out.

Does anyone know, where this might come from and what I can do as Storybook states on their website that there should be "zero-configuration" for typescript. Am I missing anything here?

Even stranger: if I run yarn start-storybook --node-resolve --watch --open everything works fine. How is this different? What mechanism is used here to compile typescript?

Here comes my .storybook/main.js

const typescript = require('rollup-plugin-typescript2');
const cpy = require('rollup-plugin-cpy');

module.exports = {
    stories: [
        
        // -----------> these are only plain javascript-packages
        '../stories/*.stories.@(js|mdx)',
        '../packages/my-javascript-ui-component/**/*.stories.@(js|mdx)',

        // -----------> breaks as soon as I include any TS-package
        // '../packages/**/*.stories.@(js|mdx)',
        // '../packages/my-evil-typescript-ui-component/**/*.stories.@(js|mdx)',
    ],

    esDevServer: {
        watch: true,
        babel: true,
        nodeResolve: true,
    },

    rollup: config => {
        config.plugins = [
            ...config.plugins,
            typescript({
                typescript: require('typescript'),
            }),
            cpy({
                files: ['**/stories/**/images/*.svg', '**/stories/**/images/*.png'],
                dest: 'public/storybook/stories/imports/images',
            }),
            cpy({
                files: ['**/material-iconfont/**'],
                dest: 'public/storybook/material-iconfont',
            }),
        ];
        return config;
    },

    addons: [
        'storybook-prebuilt/addon-knobs/register.js',
        'storybook-prebuilt/addon-docs/register.js',
    ],
};

package.json:

{
    "name": "frontend-monorepo",
    "version": "4.0.0",
    "private": true,
    "workspaces": [
        "packages/*"
    ],
    "dependencies": {
        "lit-element": "2.4.0"
    },
    "devDependencies": {
        "@babel/cli": "^7.8.4",
        "@babel/core": "^7.9.0",
        "@babel/plugin-proposal-class-properties": "^7.8.3",
        "@babel/plugin-proposal-decorators": "^7.8.3",
        "@babel/plugin-proposal-private-methods": "^7.8.3",
        "@babel/plugin-syntax-dynamic-import": "^7.8.3",
        "@babel/plugin-transform-modules-systemjs": "^7.12.0",
        "@babel/preset-typescript": "^7.8.3",
        "@open-wc/demoing-storybook": "2.4.7",
        "@open-wc/eslint-config": "3.0.0",
        "@open-wc/testing": "2.5.32",
        "@open-wc/testing-karma": "4.0.9",
        "@rollup/plugin-commonjs": "17.1.0",
        "@rollup/plugin-node-resolve": "11.1.1",
        "@rollup/plugin-replace": "2.3.4",
        "@types/resize-observer-browser": "^0.1.4",
        "babel-eslint": "10.1.0",
        "concurrently": "5.3.0",
        "deepmerge": "4.2.2",
        "es-dev-server": "1.60.2",
        "eslint-config-prettier": "6.15.0",
        "eslint-plugin-babel": "5.3.1",
        "eslint-plugin-chai-friendly": "0.6.0",
        "eslint-plugin-mocha-no-only": "1.1.1",
        "eslint-plugin-prettier": "3.2.0",
        "fetch-mock": "9.10.4",
        "karma-junit-reporter": "2.0.1",
        "lerna": "3.22.1",
        "pre-commit": "1.2.2",
        "prettier": "2.2.1",
        "rimraf": "^2.7.1",
        "rollup": "2.38.5",
        "rollup-plugin-cleanup": "3.2.1",
        "rollup-plugin-cpy": "2.0.1",
        "rollup-plugin-index-html": "1.12.7",
        "rollup-plugin-terser": "7.0.2",
        "rollup-plugin-typescript2": "0.29.0",
        "rollup-plugin-workbox": "6.1.1",
        "sinon": "9.2.1",
        "typescript": "4.0.5",
        "web-component-analyzer": "1.1.6"
    },
    "scripts": {
        "clean": "rimraf build && mkdir build",
        "compile": "yarn run clean && tsc -d --outDir ./build/compile",
        "build": "yarn run compile && rollup -c",
        "storybook": "start-storybook --node-resolve --watch --open",
        "storybook:clean": "rimraf public/storybook",
        "storybook:build": "yarn run storybook:clean && build-storybook -o public/storybook"
    }
}