This was a very interesting presentation, but I think the author is too wedded to immutability to just come out and state the obvious: it’s a solution in search

This was a very interesting presentation, but I think the author is too wedded to immutability to just come out and state the obvious: it’s a solution in search of a problem, and there’s not much good in using it as is. Yes, IF your problem can be decomposed into pure functional bits, that often makes a program easier to read. But if not, it’s wishful thinking to try bolting immutability onto the problem and hope that it helps. Returning state new objects is a sign that this problem doesn’t decompose the proper way to benefit from this approach! In game dev, there’s a popular pattern called “Entity Component System” which deals with these problems quite well. The components are just blobs of pure data, like the state in the article, but instead of freezing them for no real reason, you compose systems to make them interact in predictable ways. It’s much easier to reason about, which makes it the right tool for this particular job.