[tuukkah]

This seems to use the js-parsons library which has not been updated in years: https://github.com/js-parsons/js-parsons

Can anyone recommend an alternative, especially for puzzles about JavaScript?

For Python, this seems relevant: https://futurecoder.io/

Their Parsons implementation seems to be one-dimensional though (the student does not have to form the correct blocks by indentation): https://github.com/alexmojaki/futurecoder/blob/d6cb1a7bf8974...