This is a super interesting approach to JS. Conceptually, it's really cool. In practice, I don't think I'd do it (at least for any projects I can think of) because explaining it to others would be difficult and representing complex logic as "commands" sounds a bit difficult.

In a weird way, it reminds me of actor frameworks though. The difference is of course the separation of effects.

One thing I wish the author would have done, though, is add some type hints. I know it's about JS, but even some jsdoc types would have helped. It was a bit hard to know at first what the input types were to these functions.