That's possible with Total.js. We offer a lot of open source apps like Flow, UI Builder (it will be released soon officially - missing only the website) and Total DB (it will be released this week - missing only the website).
Of course, we have some premium components (under the MIT license) that are hidden. Also you can create Flow components directly in Flow, that's amazing!
Total DB: https://github.com/totaljs/totaldb UI Builder: https://uibuilder.totaljs.com/
We're preparing tutorials and you will see that it's possible to do it very easily :)